Okra ( Abelmoschus esculentus L. Moench) is a traditional pod vegetable widely grown in low, medium and high-input systems for domestic and export markets. The economic and ecological sustainability of okra in these systems is under question because of the low-yielding potential, sub-optimal pod quality and susceptibility to biotic and biotic stresses especially the yellow vein mosaic virus (YVMV) of the traditionally cultivated open-pollinated varieties (OPVs) and landraces. Development and use of improved varieties with high yield potential, superior pod quality and resistance to YVMV play an important role in bringing sustainability of okra in these systems. Fifteen single cross hybrids developed by crossing six newly developed inbred lines (RNOYR-14, RNOYR-15, RNOYR-16, RNOYR-17, RNOYR-18 and RNOYR-24), in half-diallel fashion during rainy season 2012, were evaluated along with three local hybrid checks [No. 64 (Mahyco), Avantika (228) (Bioseed) and Shakti (Nunhems)], one OPV check (Arka Anamika) and one OPV cross check for YVMV susceptibility (Pusa Sawani) in a randomized complete block design with three replications during summer 2013 at the Vegetable Research Station, Hyderabad for studying their yield potential, pod quality and resistance to YVMV. All of the 15 single cross hybrids were resistant to YVMV with 0% incidence as against 100% incidence in OPV checks Arka Anamika and Pusa Sawani. On the basis of mean performance, three crosses RNOYR-15 × RNOYR-16, RNOYR-16 × RNOYR-17 and RNOYR-17 × RNOYR-18 were of significantly higher yield potential than the standard check “No. 64”, but of comparable yield potential with other checks “Avantika” and “Shakti”. In addition, these three crosses also of superior pod quality could be exploited for development of commercial hybrid okra. These hybrids would be advantageous for production and quality improvement, trade facilitation and environmental protection.
Okra or ladies finger (Abelmoschus esculentus L. Moench) is an important vegetable crop of the Malvaceae family. Okra is said to have originated in tropical Africa [
Okra is a drought and heat tolerant crop [
In India, okra is grown in area of 0.530785 million hectares and has production of 6.350266 million tonnes green pods, whereas productivity of the crop is 12.00 t/ha [
Thus keeping in view the importance of F1 hybrids in addressing the aforesaid problems of okra growing, the present study was undertaken 1) to characterize the single cross hybrids on the basis of qualitative traits, 2) to evaluate the mean performance of single cross hybrids for pod yield and its components, 3) to determine the quality of single cross hybrids, 4) to screen the single cross hybrids for resistance to YVMV and 5) to identify the promising varieties for commercial exploitation.
The experimental material consisted of the fifteen single cross F1 hybrids developed by crossing six newly developed, nearly homozygous, horticulturally superior, optimally divergent and YVMV resistant inbred lines of okra (RNOYR-14, RNOYR-15, RNOYR-16, RNOYR-17, RNOYR-18 and RNOYR-24), in half-diallel fashion during rainy season 2012, which were evaluated along with three hybrid checks [No. 64 (Mahyco), Avantika (228), (Bioseed) and Shakti (Nunhems)] and two OPV checks (Pusa Sawani and Arka Anamika) during summer 2013 at the Vegetable Research Station, Hyderabad for studying their yield potential, pod quality and resistance to YVMV. Hyderabad comes under semi arid tropics with a tropical wet and dry climate.
For comparison of horticultural superiority, the above commercial hybrid checks were included as cross- checks. For screening against YVMV, the above commercial OPV checks which were YVMV resistant when developed but highly susceptible to YVMV at present were included as cross-checks. The Experimental Farm is situated at 17.19˚N, 79.23˚E and 542.6 m above mean sea level. The soils are sandy loams.
The experimental design used for this study is the randomized block design. The number of replications was three. Each block was subdivided into 26 plots corresponding to the 26 entries of okra studied. Each entry was grown in a double-row plot. The unit plot size was 3.0 × 1.2 m. The plants were spaced 60 cm apart between rows and 30 cm apart between plants. Each row had 10 plants, while each plot and entry had 20 plants. All agronomic practices were kept constant for whole of the experiment. Recommended package of practices was followed to raise a successful crop. Regular plant protection measures were carried out to safeguard the crop from pests and diseases.
The data on 18 qualitative characters based on descriptors for Abelmoschus esculentus [
The mean performance of parents, hybrids and checks regarding pod yield and its components was worked out. The data recorded for different characters were analyzed for variance in accordance with the standard technique [
The analysis of variance (
The range of mean values of parents as a group (
Character | Sum of squares | ||
---|---|---|---|
Replications (2) | Treatments (25) | Error (50) | |
Plant height (cm) | 22.783 | 14437.013** | 4149.666 |
Number of branches per plant | 0.021 | 11.125** | 1.588 |
Internodal length (cm) | 0.024 | 20.148** | 2.149 |
Days to 50% flowering | 1.719 | 14.158 | 23.613 |
First flowering node | 0.306 | 4.622* | 5.026 |
First fruiting node | 0.306 | 4.622* | 5.026 |
Fruit length (cm) | 0.219 | 41.220** | 21.990 |
Fruit width (cm) | 0.002 | 0.336* | 0.247 |
Fruit weight (g) | 0.641 | 121.132* | 104.066 |
Total number of fruits per plant | 13.422 | 1493.094* | 375.267 |
Number of marketable fruits per plant | 17.454 | 1811.981** | 442.928 |
Total yield per plant (g) | 2785.125 | 471639.302** | 128951.109 |
Marketable yield per plant (g) | 3635.293 | 534393.169** | 117778.651 |
* , **Significant at P = 0.05 and 0.01 levels, respectively; values in parenthesis denote degrees of freedom.
Character | Average performance | |||
---|---|---|---|---|
Parental lines | Cross combinations | Hybrid checks | OPV checks | |
Plant height (cm) | 114.83 | 122.21 | 129.78 | 131.79 |
Number of branches per plant | 1.48 | 1.58 | 2.04 | 1.74 |
Internodal length (cm) | 3.74 | 4.05 | 4.33 | 5.30 |
Days to 50% flowering | 40.28 | 40.24 | 39.89 | 39.67 |
First flowering node | 4.83 | 4.91 | 4.78 | 5.00 |
First fruiting node | 4.83 | 4.91 | 4.78 | 5.00 |
Fruit length (cm) | 13.47 | 14.10 | 14.68 | 13.02 |
Fruit width (cm) | 1.73 | 1.70 | 1.73 | 1.74 |
Fruit weight (g) | 16.80 | 17.76 | 18.91 | 15.91 |
Total number of fruits per plant | 23.73 | 28.69 | 33.19 | 24.27 |
Number of marketable fruits per plant | 19.96 | 25.31 | 29.51 | 15.99 |
Total yield per plant (g) | 298.48 | 385.99 | 473.83 | 291.64 |
Marketable yield per plant (g) | 250.79 | 341.97 | 428.27 | 191.92 |
YVMV infestation on plants (%) | 0.00 | 0.00 | 2.11 | 100.00 |
YVMV = Yellow vein mosaic virus; OPV = Open pollinate variety.
g) followed by marketable yield per plant (226.55 to 291.46 g) and plant height (101.93 to 128.90 cm). The range of mean values of crosses as a group was highest for total yield per plant (286.65 to 525.65 g) followed by marketable yield per plant (236.65 to 483.35 g) and plant height (94.09 to 149.67 cm). Single cross hybrids and their parental lines had 0% incidence of YVMV. Susceptible national OPV checks had 100%, while hybrid local hybrid checks had 2.11% incidence of YVMV.
Mean performance of the growth attributes is presented in
Entry | Plant height (cm) | Number branches per plant | Internodal length (cm) | Days to 50% flowering | First flowering node | First fruiting node |
---|---|---|---|---|---|---|
Single cross hybrids | ||||||
RNOYR-14 × RNOYR-15 | 120.87 | 1.47 | 3.81 | 40.00 | 5.00 | 5.00 |
RNOYR-14 × RNOYR-16 | 123.11 | 1.73 | 4.47 | 40.00 | 4.67 | 4.67 |
RNOYR-14 × RNOYR-17 | 115.09 | 1.33 | 4.04 | 39.67 | 4.33 | 4.33 |
RNOYR-14 × RNOYR-18 | 106.67 | 1.20 | 3.57 | 40.33 | 5.00 | 5.00 |
RNOYR-14 × RNOYR-24 | 93.18 | 1.70 | 3.17 | 40.33 | 5.00 | 5.00 |
RNOYR-15 × RNOYR-16 | 149.67 | 2.13 | 4.47 | 40.00 | 5.00 | 5.00 |
RNOYR-15 × RNOYR-17 | 128.20 | 1.47 | 4.35 | 40.33 | 5.33 | 5.33 |
RNOYR-15 × RNOYR-18 | 126.27 | 1.60 | 4.17 | 40.33 | 5.00 | 5.00 |
RNOYR-15 × RNOYR-24 | 131.79 | 1.40 | 4.20 | 40.33 | 5.00 | 5.00 |
RNOYR-16 × RNOYR-17 | 145.63 | 1.93 | 4.69 | 40.33 | 4.33 | 4.33 |
RNOYR-16 × RNOYR-18 | 124.77 | 1.87 | 4.14 | 40.67 | 5.00 | 5.00 |
RNOYR-16 × RNOYR-24 | 112.07 | 1.40 | 3.87 | 40.33 | 5.00 | 5.00 |
RNOYR-17 × RNOYR-18 | 135.73 | 1.47 | 4.07 | 40.00 | 5.00 | 5.00 |
RNOYR-17 × RNOYR-24 | 125.95 | 1.73 | 4.32 | 40.67 | 5.00 | 5.00 |
RNOYR-18 × RNOYR-24 | 94.09 | 1.20 | 3.47 | 40.33 | 5.00 | 5.00 |
Parental inbred lines | ||||||
RNOYR-14 | 114.60 | 1.57 | 3.52 | 40.00 | 5.00 | 5.00 |
RNOYR-15 | 128.90 | 1.10 | 3.77 | 40.67 | 4.67 | 4.67 |
RNOYR-16 | 119.77 | 2.37 | 3.88 | 40.17 | 4.33 | 4.33 |
RNOYR-17 | 113.53 | 0.90 | 3.42 | 41.17 | 5.00 | 5.00 |
RNOYR-18 | 101.93 | 1.00 | 3.61 | 40.00 | 5.00 | 5.00 |
RNOYR-24 | 110.27 | 1.93 | 4.23 | 39.67 | 5.00 | 5.00 |
Hybrid checks | ||||||
No. 64 | 126.19 | 2.33 | 4.44 | 40.33 | 4.67 | 4.67 |
Avantika | 129.19 | 2.13 | 4.27 | 39.67 | 5.00 | 5.00 |
Shakti | 133.95 | 1.67 | 4.29 | 39.67 | 4.67 | 4.67 |
OPV checks | ||||||
Pusa Sawani | 133.75 | 1.83 | 5.42 | 39.00 | 5.00 | 5.00 |
Arka Anamika | 129.82 | 1.64 | 5.18 | 40.33 | 5.00 | 5.00 |
CV (%) | 7.46 | 10.99 | 5.04 | 1.71 | 6.50 | 6.50 |
CD (5%) | 14.95 | 0.29 | 0.34 | NS | 0.52 | 0.52 |
OPV = Open pollinate variety.
ranged from 101.93 cm (RNOYR-18) to 128.90 cm (RNOYR-15) and 93.18 cm (RNOYR-14 × RNOYR-24) to 149.67 cm (RNOYR-15 × RNOYR-16), respectively. The hybrid RNOYR-15 × RNOYR-16 (149.67 cm) was significantly taller than all the three hybrid checks while RNOYR-16 × RNOYR-17 (145.63 cm) was significantly taller than the “No. 64” and “Avantika”. None of the parents were significantly taller than the three hybrid checks. Number of branches per plant varied from 0.90 cm (RNOYR-17) to 2.37 cm (RNOYR-16) and 1.20 cm (RNOYR-18 × RNOYR-24) to 2.13 cm (RNOYR-15 × RNOYR-16) among the parents and hybrids, respectively. The hybrids RNOYR-15 × RNOYR-16 (2.13 cm) and RNOYR-16 × RNOYR-17 (1.93 cm) had significantly higher number of branches per plant than “Shakti”. The parents RNOYR-16 and RNOYR-24 had significantly more number of branches per plant than “Avantika” and “Shakti”, respectively. Internodal length varied from 3.42 (RNOYR-17) to 4.23 (RNOYR-24) among the parents and 3.17 (RNOYR-14 × RNOYR-24) to 4.69 (RNOYR-16 × RNOYR-17) among the hybrids. Among 15 hybrids, five hybrids RNOYR-14 × RNOYR-15 (3.81), RNOYR-14 × RNOYR-18 (3.57), RNOYR-14 × RNOYR-24 (3.17), RNOYR-16 × RNOYR-24 (3.87) and RNOYR-18 × RNOYR-24 (3.47) had significantly shorter internodal length than all the three hybrid checks. Almost all parents expect RNOYR-24 had significantly shorter internodal length than all the three hybrid checks.
The parents, their hybrids, hybrid checks and OPV checks did not differ significantly for days to 50% flowering (
Mean performance of the fruit attributes is presented in
None of the parents and hybrids had significantly wider fruits than all the three checks. Fruit weight of the parents and hybrids varied from 15.69 g (RNOYR-24) to 18.20 g (RNOYR-18) and 15.41 g (RNOYR-14 × RNOYR-17) to 19.76 g (RNOYR-15 × RNOYR-18), respectively. None of the parents and hybrids had significantly heavier fruits than any of the three hybrid checks. Total number of fruits produced by the parents and hybrids ranged from 20.73 (RNOYR-18) to 27.67 (RNOYR-16) and 23.09 (RNOYR-18 × RNOYR-24) to 37.12 (RNOYR-15 × RNOYR-16), respectively. The hybrid RNOYR-15 × RNOYR-16 produced significantly more total number of fruits per plant than the check No. 64 (36.42). Number of marketable fruits produced by the parents and hybrids ranged from 16.73 (RNOYR-18) to 24.00 (RNOYR-16) and 19.09 (RNOYR-18 × RNOYR-24) to 33.79 (RNOYR-15 × RNOYR-16), respectively. Only one hybrid RNOYR-15 × RNOYR-16 (33.79) had produced significantly more number of marketable fruits per plant than the check “No. 64” (27.77 g).
Mean performance of the entries for yield attributes is presented in
Fifteen half-diallel crosses characterized in this study showed a broad variation for most traits (
Entry | Fruit length (cm) | Fruit width (cm) | Fruit weight (g) | Total no. of fruits per plant | No. of marketable fruits per plant | Total yield per plant (g) | Marketable yield per plant (g) | YVMV infestation (%) |
---|---|---|---|---|---|---|---|---|
Single cross hybrids | ||||||||
RNOYR-14 × RNOYR-15 | 14.61 | 1.58 | 17.98 | 29.08 | 25.75 | 392.63 | 347.61 | 0.00 (R) |
RNOYR-14 × RNOYR-16 | 13.99 | 1.68 | 17.26 | 26.57 | 23.57 | 343.36 | 304.91 | 0.00 (R) |
RNOYR-14 × RNOYR-17 | 14.23 | 1.58 | 15.41 | 25.85 | 22.51 | 298.88 | 260.92 | 0.00 (R) |
RNOYR-14 × RNOYR-18 | 13.45 | 1.77 | 17.52 | 25.91 | 22.58 | 340.68 | 297.19 | 0.00 (R) |
RNOYR-14 × RNOYR-24 | 13.89 | 1.72 | 18.28 | 27.84 | 24.18 | 381.95 | 332.15 | 0.00 (R) |
RNOYR-15 × RNOYR-16 | 14.37 | 1.77 | 18.64 | 37.12 | 33.79 | 525.65 | 483.35 | 0.00 (R) |
RNOYR-15 × RNOYR-17 | 13.33 | 1.71 | 16.09 | 26.51 | 23.17 | 318.67 | 278.20 | 0.00 (R) |
RNOYR-15 × RNOYR-18 | 14.61 | 1.84 | 19.76 | 28.17 | 25.17 | 416.29 | 371.43 | 0.00 (R) |
RNOYR-15 × RNOYR-24 | 14.82 | 1.69 | 17.65 | 28.34 | 25.34 | 375.05 | 335.44 | 0.00 (R) |
RNOYR-16 × RNOYR-17 | 14.72 | 1.70 | 18.63 | 35.41 | 31.75 | 495.22 | 450.90 | 0.00 (R) |
RNOYR-16 × RNOYR-18 | 13.59 | 1.73 | 17.22 | 29.49 | 26.16 | 379.39 | 337.13 | 0.00 (R) |
RNOYR-16 × RNOYR-24 | 14.07 | 1.71 | 18.99 | 25.61 | 22.28 | 365.79 | 318.60 | 0.00 (R) |
RNOYR-17 × RNOYR-18 | 14.85 | 1.68 | 18.21 | 33.62 | 29.95 | 489.90 | 440.60 | 0.00 (R) |
RNOYR-17 × RNOYR-24 | 14.33 | 1.70 | 18.25 | 27.77 | 24.43 | 380.07 | 334.50 | 0.00 (R) |
RNOYR-18 × RNOYR-24 | 12.67 | 1.72 | 16.51 | 23.09 | 19.09 | 286.29 | 236.65 | 0.00 (R) |
Parental inbred lines | ||||||||
RNOYR-14 | 14.37 | 1.69 | 17.23 | 23.33 | 19.67 | 301.81 | 254.26 | 0.00 (R) |
RNOYR-15 | 13.37 | 1.68 | 15.85 | 24.73 | 20.73 | 295.06 | 247.96 | 0.00 (R) |
RNOYR-16 | 13.83 | 1.74 | 16.15 | 27.67 | 24.00 | 335.66 | 291.46 | 0.00 (R) |
RNOYR-17 | 12.59 | 1.80 | 17.68 | 22.67 | 19.33 | 301.70 | 257.02 | 0.00 (R) |
RNOYR-18 | 13.03 | 1.81 | 18.20 | 20.73 | 16.73 | 281.85 | 226.55 | 0.00 (R) |
RNOYR-24 | 13.63 | 1.64 | 15.69 | 23.27 | 19.27 | 274.82 | 227.50 | 0.00 (R) |
Hybrid checks | ||||||||
No. 64 | 14.37 | 1.73 | 18.19 | 31.43 | 27.77 | 429.16 | 400.88 | 0.00 (R) |
Avantika | 15.01 | 1.73 | 19.35 | 33.10 | 30.10 | 482.04 | 438.20 | 8.33 (T) |
Shakti | 14.67 | 1.74 | 19.20 | 35.03 | 30.66 | 510.29 | 445.73 | 8.33 (T) |
OPV checks | ||||||||
Pusa Sawani | 12.31 | 1.85 | 16.53 | 20.27 | 12.87 | 254.77 | 161.63 | 100.00 (HS) |
Arka Anamika | 13.73 | 1.63 | 15.28 | 28.27 | 19.10 | 328.50 | 222.20 | 100.00 (HS) |
CV (%) | 4.75 | 4.09 | 8.23 | 9.89 | 12.49 | 13.78 | 15.19 | - |
CD (5%) | 1.08 | 0.11 | 2.36 | 4.50 | 4.88 | 83.30 | 79.62 | - |
OPV = Open pollinate variety; Values in parenthesis denote YVMV disease reaction; YVMV = Yellow vein mosaic virus; HS = Highly susceptible; R = Resistant; T = Tolerant.
F1 hybrid | Plant growth habit | Branching habit | Stem colour | Stem pubescence | Mature leaf colour | Leaf rib colour |
---|---|---|---|---|---|---|
Single cross hybrids | ||||||
RNOYR-14 × RNOYR-15 | Erect | Low | Green | Smooth | Green | Green |
RNOYR-14 × RNOYR-16 | Erect | Low | Green | Smooth | Green | Green |
RNOYR-14 × RNOYR-17 | Erect | Low | Green | Smooth | Green | Green |
RNOYR-14 × RNOYR-18 | Erect | Low | Green | Smooth | Green | Green |
RNOYR-14 × RNOYR-24 | Erect | Low | Green | Smooth | Green | Green |
RNOYR-15 × RNOYR-16 | Erect | Low | Green with purple tinge | Smooth | Green | Green |
RNOYR-15 × RNOYR-17 | Erect | Low | Green with purple tinge | Slightly rough | Green | Green |
RNOYR-15 × RNOYR-18 | Erect | Low | Green with purple tinge | Slightly rough | Green | Green |
RNOYR-15 × RNOYR-24 | Erect | Low | Green with purple tinge | Slightly rough | Green | Green |
RNOYR-16 × RNOYR-17 | Erect | Low | Green with purple tinge | Smooth | Green | Green |
RNOYR-16 × RNOYR-18 | Erect | Low | Green | Slightly rough | Green | Green |
RNOYR-16 × RNOYR-24 | Erect | Low | Green | Smooth | Green | Green |
RNOYR-17 × RNOYR-18 | Erect | Low | Green with purple tinge | Slightly rough | Green | Green |
RNOYR-17 × RNOYR-24 | Erect | Low | Green with purple tinge | Smooth | Green | Green |
RNOYR-18 × RNOYR-24 | Erect | Low | Green with purple tinge | Smooth | Green | Green |
Hybrid checks | ||||||
No. 64 | Erect | Low | Green | Smooth | Green | Green |
Avantika | Erect | Low | Green | Smooth | Green | Green |
Shakti | Erect | Low | Green | Smooth | Green | Green |
OPV checks | ||||||
Pusa Sawani | Erect | Low | Green with purple tinge | Smooth | Green | Green |
Arka Anamika | Erect | Low | Green with purple tinge | Smooth | Green | Green |
F1 hybrid | Leaf lobing | Leaf pubescence | Petiole colour | Petal colour | Outside petal base colour | Shape of epicalyx segments |
---|---|---|---|---|---|---|
Single cross hybrids | ||||||
RNOYR-14 × RNOYR-15 | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-14 × RNOYR-16 | Deeply lobed | Downy | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-14 × RNOYR-17 | Deeply lobed | Downy | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-14 × RNOYR-18 | Shallowly lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-14 × RNOYR-24 | Deeply lobed | Downy | Green | Yellow | Yellow | Lanceolate |
RNOYR-15 × RNOYR-16 | Deeply lobed | Downy | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-15 × RNOYR-17 | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
---|---|---|---|---|---|---|
RNOYR-15 × RNOYR-18 | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-15 × RNOYR-24 | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-16 × RNOYR-17 | Deeply lobed | Downy | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-16 × RNOYR-18 | Shallowly lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-16 × RNOYR-24 | Deeply lobed | Downy | Green | Yellow | Yellow | Lanceolate |
RNOYR-17 × RNOYR-18 | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-17 × RNOYR-24 | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
RNOYR-18 × RNOYR-24 | Shallowly lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
Hybrid checks | ||||||
No. 64 | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
Avantika | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
Shakti | Deeply lobed | Slightly rough | Green with red colour | Yellow | Red | Lanceolate |
OPV checks | ||||||
Pusa Sawani | Shallowly lobed | Downy | Green with red colour | Yellow | Red | Lanceolate |
Arka Anamika | Shallowly lobed | Downy | Green with red colour | Yellow | Red | Lanceolate |
F1 hybrid | Position of fruit on stem | Fruit shape | Immature fruit colour | Fruit pubescence | Number of ridges per fruit | Protrusion of seeds through epidermis |
---|---|---|---|---|---|---|
Single cross hybrids | ||||||
RNOYR-14 × RNOYR-15 | Semi erect | Angular | Green | Downy | 5 | Absent |
RNOYR-14 × RNOYR-16 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-14 × RNOYR-17 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-14 × RNOYR-18 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-14 × RNOYR-24 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-15 × RNOYR-16 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-15 × RNOYR-17 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-15 × RNOYR-18 | Semi erect | Angular | Green | Downy | 5 | Absent |
RNOYR-15 × RNOYR-24 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-16 × RNOYR-17 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-16 × RNOYR-18 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-16 × RNOYR-24 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-17 × RNOYR-18 | Erect | Angular | Dark green | Downy | 5 | Absent |
RNOYR-17 × RNOYR-24 | Erect | Angular | Green | Downy | 5 | Absent |
RNOYR-18 × RNOYR-24 | Erect | Angular | Green | Downy | 5 | Absent |
Hybrid checks | ||||||
No. 64 | Erect | Angular | Green | Downy | 5 | Absent |
Avantika | Erect | Angular | Green | Downy | 5 | Absent |
Shakti | Erect | Angular | Green | Downy | 5 | Absent |
OPV checks | ||||||
Pusa Sawani | Erect | Angular | Green | Downy | 5 | Absent |
Arka Anamika | Erect | Angular | Green | Downy | 5 | Absent |
OPV = Open pollinate variety.
leaf pubescence (downy and slightly rough), separately. Hybrids were grouped into two groups on the basis of their stem colour (green and green with purple tinge) and stem pubescence (smooth and slightly rough), separately. Although, there were no differences in petal color, clear cut difference was found in outside petal base colour (red and yellow) among the hybrids. There was no difference in shape of epicalyx segments (only lanceolate) among the hybrids. The fruits of all hybrids under study had erect position on main stem except RNOYR-14 × RNOYR-15 and RNOYR-15 × RNOYR-18 (semi-erect), downy pubescence and green immature fruit colour except RNOYR-17 × RNOYR-18 (dark green), five ridges and angular shape.
The variation in leaf shape, leaf pubescence, stem colour, stem pubescence, petiole colour, outside petal base colour, immature fruit colour and position of fruit on main stem, were easily recognizable with visual appraisal in the material. Fruits displayed diversity in colour (green/dark green) and its position on main stem (erect/ semi-erect). Fruits with characteristics such as smooth, spineless, slender with green (green/dark green) skin are very desirable in the Indian local and export markets. RNOYR-15, RNOYR-17 and RNOYR-18 were among the parental lines and RNOYR-17 × RNOYR-18 was among the crosses that had dark green fruits. In the present study, the comparative view of fruits of six parental lines, their fifteen crosses and three hybrid checks is depicted in
Field screening under natural epiphytotic conditions during summer at Hyderabad indicated that none of the15 single cross hybrids and their 6 parental inbred lines had any incidence of YVMV (0% incidence) on plants at final harvest (
their 6 parental inbred lines under study were found to be resistant to YVMV under field conditions. Of the three hybrid checks under study, “No. 64” was found to be resistant, while “Avantika” and “Shakti” were found to be tolerant. Both of the two susceptible checks viz., “Arka Anamika” and “Pusa Sawani” were found to be highly susceptible with 100% YVMV incidence on plants.
To turn okra into a perfect candidate for sustainable agriculture, the cultivated variety should be attractive to both producers and consumers in terms of yield and quality (horticultural superiority), respectively [
In general, the significant differences (P ≤ 0.05) revealed among the agro-economic traits may be due to environmental influences on the genotypes as well as differences in the genetic potential of the different okra genotypes (parental lines, crosses, hybrid checks and OPV checks). This corroborates findings of earlier researchers [
In okra, of the thirteen agro-economic traits under study, high mean values are desirable for plant height, number of branches per plant, fruit length, fruit width and fruit weight, total number of fruits per plant, number of marketable fruits per plant, total yield per plant and marketable yield per plant, while low mean values are desirable for internodal length, days to 50% flowering, first flowering node and first fruiting node. Plant height, number of branches per plant and internodal length largely determine the fruit bearing surface and were considered as important growth attributes. Okra bears pods at almost all nodes on main stem. Higher the plant height, higher is the number of fruits per plant because of accommodation of more number of nodes for a given internodal length. Higher the number of branches on the main stem, higher is the number of fruits per plant because of accommodation of more number of nodes per plant. Shorter distance between nodes accommodates more number of nodes on main stem, which will ultimately lead to higher fruit number and higher fruit production. Hence, high mean value is desirable for plant height and number of branches per plant, while low mean value is desirable for internodal length to accommodate more number of nodes and to get higher fruit yield in okra. Days to 50% flowering, first flowering node and first fruiting node are the indicators of earliness in okra. Earliness is one of the main objectives of okra breeding. Earliness, expressed by the lower leaf axils in which flower buds appear is partly due to varietal characteristic. It allows completion of pickings before the crop suffers damages from unfavorable climatic conditions. Early flowering not only gives early pickings and better returns but also widens fruiting period of the plant. In addition, it also reduces the losses due to the attack of insects and diseases. Days to 50% flowering are of importance in the sense that if flowering starts earlier, sufficient time will be available for flowering and fruit formation process. Thus, early flowering is desirable in okra and the genotypes with early flowering habit are desirable. Flowering and fruiting at lower nodes are helpful in increasing the number of fruits per plant as well as getting early yields. Days to 50% flowering, first flowering node and first fruiting node are the effective traits for earliness. Low mean value is highly desirable for all these three attributes of earliness. Fruit length, width, weight and number are considered to be the fruit traits in okra, for which high mean value is desirable.
Optimizing pod yield is one of the most important goals for most okra growers and, consequently, most okra breeding programs [
Variation is an important attribute in breeding programs [
Among the eighteen qualitative characters studied, there exists relationship between the stem colour of the accessions and the fruit colour as well as their petiole colour. The relationship was stronger between the stem colour and the fruit colour than between the stem colour and petiole colour of the accessions. The same trend was observed between the stem pubescence and the fruit pubescence. These may probably be as a result of one gene controlling the pair of traits of stem and fruit colour and stem and fruit pubescence in the various accessions. This was also reported by other researcher [
Vegetable product innovation is necessary for maintaining the interest of today’s consumer. Quality in vegetable crops, in contrast to field crops, is often more important than yield. For farmers to survive, varieties must be accepted by the market. Thus, quality is usually more important than productivity. The final goal of vegetable breeding programs is then to release new varieties having elite combinations of many desirable horticultural characteristics. In addition to pod yield, pod quality plays an important role in okra productivity and marketability [
One important factor in producing quality okra pods is the selection of superior varieties. Although F1 hybrids are not perfect, they are generally superior in quality and should be chosen to fit our specific needs. In the present study, all of the 15 hybrids and three hybrid checks under present study were of superior pod quality as evident from the qualitative traits. The findings of this study are important by their relevance to both, consumer preferences and the needs of genetic improvement in okra. On the whole, most of these hybrids under present study would be advantageous for quality improvement, trade facilitation and consumer protection.
There is potential of increased pod yields through use of F1 hybrids in okra. On the basis of mean performance for pod yield and its components and acceptable pod quality traits, three crosses RNOYR-15 × RNOYR- 16, RNOYR-6 × RNOYR-17 and RNOYR-17 × RNOYR-18 were of statistically higher yield potential than the check “No. 64” and of statistically comparable yield potential with the hybrid checks “Avantika” and “Shakti”. However, for more conclusive results there is need to subject the F1 hybrids to the other two growing seasons and regions of the state.
Plant diseases continue to play a major limiting role in agricultural production. The control of plant diseases using classical pesticides raises serious concerns about food safety, environmental quality and pesticide resistance, which have dictated the need for alternative pest management techniques. It is important to find alternative measures to control plant diseases which do not harm the environment and at the same time increase yield and improve product quality [
Viruses can substantially reduce production and quality and are becoming increasingly problematic worldwide due to the absence of virus resistant germplasm for many important vegetable crops. Viruses pose serious constraints to okra production. Okra is susceptible to at least 19 plant viruses [
Selecting F1 hybrids and disease resistant cultivars cannot be stressed enough, in choosing wisely, farmers avoid many disease problems in the field. In okra, the easiest method of screening genotypes against YVMV is the field screening in the hotspot regions. In screening okra genotypes to YVMV, selection of the screening region as hot-spot is most important. Once the hot-spot region is selected, the selection of suitable screening season is also important. The role of environmental conditions cannot be denied in case of creation of epiphytotic situations in YVMV disease of okra. Each parameter of environment plays its role in reducing or enhancing of pathogenic activity as well as vectors especially insect vectors. Hot weather with little or no rainfall was conducive for disease progress of YVMV and also for multiplication of Bemisia tabaci [
Results of the field screening under hot spot area indicated zero percent incidence of YVMV in all of the 15 hybrids and their 6 parental inbred lines, while 100 percent incidence of YVMV in the two OPV checks “Pusa Sawani” and “Arka Anamika” used as cross-checks at final harvest. All of the 15 hybrids and their 6 parental inbred lines under study were found to be resistant to YVMV under field conditions. Of the three hybrid checks under study, “No. 64” was found resistant, while “Avantika” and “Shakti” were tolerant to YVMV. These could be useful sources of resistant genes which could be exploited in breeding okra cultivars resistant to YVMV. It was evident from the results of the present study that tolerance/resistance in okra is genetic and not due to escape. Of the 51 okra hybrids screened for YVMV resistance four hybrids were highly resistant to YVMV, while the rest of the hybrids were susceptible or highly susceptible [
In conclusion, the analysis of variance revealed a wide range of variation for almost all the characters studied. Further, the present study revealed horticultural superiority and YVMV resistance of certain single cross hybrids over hybrid checks. The single cross hybrids RNOYR-15 × RNOYR-16, RNOYR-16 × RNOYR-17 and RNOYR-17 × RNOYR-18 with high yield potential, good fruit quality and YVMV resistance have got the potential of being commercially exploited for the production of F1 hybrids in okra after further multi-environment testing. These hybrids would be advantageous for production and quality improvement, trade facilitation and environmental protection. The results of this study would help okra breeders to develop not only productive varieties but also those with YVMV resistance and superior pod quality attributes. In perspective, it would be judicious to produce F1 hybrids and to evaluate their yield potential and pod quality. This could probably the first report of developing horticulturally superior and YVMV resistant single cross hybrids of okra in the world.
Shashi Kumar,Medagam Thirupathi Reddy, (2015) Morphological Characterization and Agronomic Evaluation of Yellow Vein Mosaic Virus Resistant Single Cross Hybrids for Yield and Quality Traits in Okra (Abelmoschus esculentus L. Moench). Open Access Library Journal,02,1-17. doi: 10.4236/oalib.1101720