Genetic diversity is one of the useful tools to select appropriate lines for hybridization. Twenty short - statured maize inbred lines were taken for present study , which were collected from CIMMYT India and Mexico through Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipur. This experiment was conducted from November 2015 to April 2016 t o identify parental lines to produce single cross short statured maize hyb rids. From th e genetic diversity studies , the importance of both additive and non-additive gene actions for the expression of yield and yield contributing characters were found. Values of vector I and II revealed that both the vectors had positive values for date of silking, plant height, rows/cob, grains/row and yield. These results indicated that these five characters had highest contribution towards divergence. Based on the relative magnitude of D2 values; 20 inbred lines were grouped into five clusters. Seven inbred lines were selected on the basis of genetic diversity and per se performance which will be crossed separately in a half - diallel fashion to develop hybrids.
“Maize (Zea mays L., 2n = 20)’’ is one of the most important cereal crops in the world. It is a major food, feed and industrial crop both in developed and developing countries. The area, production and yield of maize have increased many folds over the last 50 years. Maize production and consumption both increase at the rate of 3.5% annually [
The experiment was carried out at the central research farm of Bangladesh Agricultural Research Institute (BARI), Gazipur to select promising and diverse inbred lines for hybridization during November 2012 to May 2013. Twenty maize inbred lines were collected from CIMMYT India, CIMMYT Mexico through Plant Breeding Division of BARI. The pedigree were as follows CML20-2-B (H08R-N8205-4), CML27-2-B (H08R-N8205-7), CML28-2-B (H08R-N8205-9), CML30-2-B (H08R-N8205-13), CML31-2-B (H08R-N8205-15), CML32-2-B (H08R-N8205-17), CML33-1-B (H08R-N8205-18), CML41-2-B (H08R-N8205-20), CML51-2-B (H08R-N8205-22), CML58-1-B (H08R-N8205-23), CML70-2-B (H08R-N8205-28), CML71-2-B (H08R-N8205-31), CML72-1-B (H08R-N8205-32), CML112-1-B (H08R-N8205-38), CML113-1-B (H08R-N8205-39), CML116-1-B (H08R-N8205-42), CML121-1-B (H08R-N8205-43), CML122-1-B (H08R-N8205-44), CML124-1-B (H08R-N8205-45), CML124-2-B (H08R-N8205-46). Among them the inbreds CML31-2-B, CML32-2-B, CML33-1-B, CML41-2-B, CML72-1-B, CML116-1-B, CML124-2-B were selected and designated as parents SP05, SP06, SP03, SP04, SP02, SP01 and SP07, respectively. The experiment was laid out following alpha lattice design [
The experimental fields were prepared by ploughing with tractor followed by harrowing and laddering to bring desirable tilth. Fertilizers recommended for inbred were applied @ 120, 80, 80, 20, 5, 1 kg∙ha−1 of N, P2O5, K2O, S, Zn, B, respectively. One third of nitrogen and the whole amount of other fertilizers were applied to the soil at the time of final land preparation. The experiments for each group of genotype were planted in two rows of 5 m. length, row to row and plant to plant spacing of 60 cm and 20 cm, respectively, Sowing was done in furrows with two seeds per hill. The seedlings emerged five to seven days after sowing. Seedlings were thinned keeping one seedling per hill after two weeks of emergence.
Standard agronomic practices were followed in trial management [
Ten randomly selected competitive plants at field maturity (5 from each row in a plot of each genotype) excluding any plant surrounding by a missing hill were used for receding observations on the following parameters: days to tasseling (DT), days to silking (DS), plant height (PH), ear height (EH), ear length (EL), ear diameter (ED), number of rows cob−1 (R/C), number of seeds row−1 (S/R), thousand grain weight (TGW), grain yield plant−1 (Y/P).
Mean performance of short statured maize inbred lines
Mean performance of the inbred lines presented in
Inbred lines | Selected genotypes | DT | DS | PH | EH | EL | ED | R/C | S/R | TGW | Y/P |
---|---|---|---|---|---|---|---|---|---|---|---|
1 | 113 | 117 | 92.0 | 39.0 | 15.6 | 3.67 | 10.8 | 21.0 | 280 | 260 | |
2 | 97 | 100 | 88.0 | 20. | 6.10 | 3.63 | 10.0 | 14.1 | 280 | 260 | |
3 | 99 | 103 | 72.0 | 21.7 | 5.0 | 3.13 | 10.0 | 10.4 | 240 | 220 | |
4 | 99 | 103 | 68.3 | 18.7 | 7.0 | 2.10 | 10.5 | 11.5 | 180 | 190 | |
5 | SP05 | 88 | 94 | 49.3 | 12.7 | 7.5 | 3.77 | 14.0 | 15.3 | 240 | 190 |
6 | SP06 | 100 | 105 | 74.7 | 20.3 | 8.4 | 3.67 | 12.8 | 14.2 | 240 | 220 |
7 | SP03 | 96 | 99 | 66.3 | 18.3 | 7.6 | 4.27 | 13.2 | 18.2 | 240 | 210 |
8 | SP04 | 95 | 97 | 70.0 | 19.3 | 9.4 | 4.13 | 14.4 | 16.2 | 240 | 250 |
9 | 87 | 89 | 99.0 | 26.0 | 7.7 | 3.67 | 10.6 | 14.7 | 220 | 240 | |
10 | 95 | 99 | 81.0 | 25.3 | 8.4 | 4.20 | 11.7 | 18.6 | 240 | 220 | |
11 | 95 | 98 | 89.3 | 30.3 | 8.0 | 4.10 | 12.0 | 15.5 | 240 | 220 | |
12 | 104 | 107 | 88.0 | 32.7 | 11.6 | 3.67 | 12.4 | 16.4 | 200 | 180 | |
13 | SP02 | 94 | 97 | 90.3 | 23.7 | 10.5 | 4.10 | 12.3 | 19.5 | 310 | 300 |
14 | 87 | 89 | 94.7 | 24.7 | 10.4 | 3.77 | 11.6 | 14.2 | 340 | 200 | |
15 | 113 | 116 | 90.3 | 29.3 | 11.3 | 3.87 | 12.0 | 20.4 | 240 | 200 | |
16 | SP01 | 94 | 97 | 85.3 | 30.0 | 12.4 | 4.33 | 14.1 | 21.4 | 270 | 330 |
17 | 97 | 101 | 66.0 | 20.6 | 7.5 | 4.10 | 12.3 | 15.0 | 310 | 150 | |
18 | 104 | 108 | 122.3 | 44.3 | 10.5 | 4.17 | 12.0 | 13.8 | 240 | 100 | |
19 | 106 | 110 | 106.0 | 47.0 | 13.6 | 3.80 | 10.8 | 16.8 | 290 | 180 | |
20 | SP07 | 88 | 91 | 86.3 | 26.7 | 9.8 | 3.07 | 12.6 | 16.2 | 290 | 280 |
Mean | 97.55 | 101.00 | 73.21 | 36.88 | 9.02 | 3.76 | 11.76 | 15.87 | 261.00 | 210.50 | |
Cv% | 7.78 | 7.78 | 20.51 | 33.36 | 28.69 | 13.81 | 11.76 | 21.26 | 14.76 | 27.20 |
DT = Days to tasseling (50%), DS = Days to silking (50%), PH = Plant height (cm), EH = Ear height (cm), EL = Ear length (cm), ED = Ear diameter (cm), R/C = Rows per cob, S/R = Seeds per Row, TGW = Thousand grains weight (gm) and Y/P = Yield/plant (gm).
The most important yield contributing characters in maize are ear length and diameter. Ear length and diameter ranged from 5.0 cm to 15.6 cm and 2.1 cm to 4.33 cm, respectively. The highest number of kernels/seeds per row was observed in line 16 followed by 15 and 1. The highest number of rows per cob was observed in line 8 followed by 15 and 1. Inbred line 14 produced the bold sized grain and showed the highest thousand grain weight, whereas line 4 gave the lowest thousand grain weights. Some of the inbred lines had thousand grain weights above or near 250g which is also a desirable character.
Duration of pollen shedding and silking ranged from 87 to 113 and 89 to 117 days, respectively. The line 1 took the longest on the other hand the line 9 took the shortest period of time for pollen shedding and silking. Generally, pollen shedding started earlier than silking. Anthesis and silking interval (ASI) of all the inbred lines evaluated in this experiment ranged from 2-4 days which could be considered as a good trait. Plant height was found highest in line 18 followed by 19 and 09 and it was found lowest in 5 followed by 7 and 17. Ear height ranged from 12.7 to 47.0 cm among the tested inbreds. Inbred line 5 also showed the shortest ear height followed by 7 and 4. In all the entries, ear placement was at or near the midpoint of the plant which is a desirable character.
Construction of scatter diagram of 20 short statured maize inbred lines
The analysis of variance showed significant variations among all the inbred lines for all the ten characters studied. Based on the values of principal component scores 2 and 1 obtained from the principal component analysis, a two-dimensional scatter diagram (Z2 - Z1) using component score 1 as X-axis and component score 2 as Y-axis was constructed, which has been presented in
Cluster analysis of 20 short statured maize inbred lines
Clustering pattern could be utilized in choosing parents for cross combination that could be produced variability for selection [
cluster V. Clusters III and IV comprised 35% and 30% of the total inbred lines (
[
Principal component analysis (PCA) of 20 short statured maize inbred lines
Ten characters were considered for genetic diversity analysis. Eigen values of ten principal axis and percentage of total variation accounting for them obtained from the principal component analysis are presented in
Principal Coordinate analysis (PCO) of 20 short statured maize inbred lines
Clusters | Number of genotypes | Inbred lines included in different clusters |
---|---|---|
I | 2 | L06, L18 |
II | 2 | L05, L12 |
III | 7 | L03, L04, L07, L08, L10, L11, L15 |
IV | 6 | L01, L02, L09, L13, L14, L16 |
V | 3 | L17, L19, L20 |
Principal component axis | Eigen values | % of total variation | Cumulative percentages |
---|---|---|---|
I | 3.7923 | 37.92 | 37.92 |
II | 2.2695 | 22.69 | 60.61 |
III | 1.4968 | 14.97 | 75.58 |
IV | 1.0220 | 10.22 | 85.80 |
V | 0.6251 | 6.25 | 92.05 |
VI | 0.4280 | 4.28 | 96.33 |
VII | 0.2160 | 2.16 | 98.49 |
VIII | 0.1209 | 1.21 | 99.70 |
IX | 0.0261 | 0.26 | 99.96 |
X | 0.0035 | 0.03 | 99.99 |
Principal Coordinate Analysis (PCO) was done to get inter genotypic distances. The highest inter genotypic distance (1.683) was observed between the lines L20 and L5 followed by the lines L16 and L5 (1.646) and lines L5 and L13 (1.644) (
Average intra and inter cluster distance of 20 short statured maize inbred lines
The inter cluster distance (
Genotypic combination | Distance (D2 Values) |
---|---|
L20 and L05 | 1.6831 |
L16 and L05 | 1.6461 |
L05 and L13 | 1.6443 |
L18 and L02 | 1.4630 |
L03 and L01 | 1.4401 |
L04 and L01 | 1.4002 |
L18 and L03 | 1.3990 |
L18 and L04 | 1.3892 |
L06 and L08 | 1.3587 |
L19 and L03 | 1.3362 |
Genotypic combination | Distance (D2 Values) |
---|---|
L03 and L15 | 0.1897 |
L11 and L10 | 0.2688 |
L15 and L12 | 0.2701 |
L14 and L13 | 0.3009 |
L10 and L08 | 0.3894 |
L16 and L14 | 0.3934 |
L17 and L07 | 0.4153 |
L16 and L13 | 0.4187 |
L03 and L02 | 0.4327 |
L15 and L10 | 0.4374 |
Cluster number | I | II | III | IV | V |
---|---|---|---|---|---|
I | 1.044 | ||||
II | 12.24 | 1.2139 | |||
III | 9.18 | 12.09 | 0.662 | ||
IV | 19.72 | 24.62 | 12.97 | 0.6577 | |
V | 19.52 | 28.19 | 16.78 | 9.65 | 0.8562 |
values between cluster II and IV, cluster I and V, I and IV indicated the lines belonging to each pair of cluster we real so far diverged.
The intra-cluster distances were calculated from these inter-genotypic distances as suggested by [
Cluster means of 20 short statured maize inbred lines
Cluster mean for 10 characters are presented in
Cluster II composed of two lines (L5 and L12) gave highest mean for rows/cob (13.20) and seed/row (18.35), second highest mean was obtained from character ear length (9.55).
Cluster III composed of seven lines (L3, L4, L7, L8, L10, L11 and L15) did not gave highest mean for any character but second highest mean was found for date of tasseling (98.86), date of silking (102.14) and seed/row (15.97).
Cluster IV composed of six lines (L1, L2, L9, L13, L14 and L16) and gave highest mean for yield/plant (280.00) and second highest mean value were obtained from ear diameter (3.86) and thousand grain weight (286.67).
Cluster V composed of 3 lines (L17, L19 and L20) and was found to give highest mean for 1000 seed wt. (313.33) and ear length (10.50), second highest mean was found for plant height (88.90), ear height (30.77).
The highest mean values for some expected yield contributing traits were identified in cluster I, II, IV and V, the second highest values of some desirable traits were grouped in cluster III, IV. Therefore, selection for higher yield can safely done from these clusters.
Latent vectors of 20 short statured maize inbred lines
Contribution of characters towards divergence of the genotypes obtained from principal component analysis (PCA) was presented in
Character | I | II | III | IV | V |
---|---|---|---|---|---|
1. DT | 102.00 | 96.00 | 98.86 | 95.50 | 96.67 |
2. DS | 106.50 | 100.50 | 102.14 | 98.50 | 100.00 |
3. PH | 98.50 | 68.65 | 76.74 | 88.82 | 88.90 |
4. EH | 32.30 | 22.70 | 23.27 | 27.57 | 30.77 |
5. EL | 8.85 | 9.75 | 8.60 | 9.92 | 10.70 |
6. ED | 3.92 | 3.72 | 3.69 | 3.86 | 3.657 |
7. R/C | 12.40 | 13.20 | 11.97 | 10.73 | 11.90 |
8. S/R | 14.0 | 18.35 | 15.97 | 15.82 | 15.33 |
9. TGW | 240.00 | 190.00 | 242.86 | 286.67 | 313.33 |
10. Y/P | 115.00 | 170.00 | 204.29 | 280.00 | 176.67 |
DT = Days to Tasseling (50%), DS = Days to Silking (50%), PH = Plant Height (cm), EH = Ear Height (cm), EL = Ear Length (cm), ED = Ear Diameter (cm), R/C = Rows per Cob, S/R = Seeds per Row, TGW = Thousand Grains Weight (gm) and Y/P = Yield/Plant (gm).
Character | Vector I | Vector II |
---|---|---|
1. DT | −0.5865 | −1.3242 |
2. DS | 0.4786 | 1.2913 |
3. PH | 0.2587 | 0.0106 |
4. EH | −0.1720 | 0.4004 |
5. EL | −1.3278 | −1.3202 |
6. ED | −1.7260 | −0.4796 |
7. R/C | 0.8771 | 1.4469 |
8. S/R | 1.0137 | 0.4056 |
9. TGW | −0.2023 | 0.0849 |
10. Y/P | 0.0294 | 0.0460 |
DT = Days to Tasseling (50%), DS = Days to Silking (50%), PH = Plant Height (cm), EH = Ear Height (cm), EL = Ear Length (cm), ED = Ear Diameter (cm), R/C = Rows per Cob, S/R = Seeds per Row, TGW = Thousand Grains Weight (gm) and Y/P = Yield/Plant (gm).
I and II revealed that both the vectors had positive values for date of silking, plant height, rows/cob, grains/row and yield. These results indicated that these five characters had highest contribution towards divergence and negative values in both the vectors for date of tasseling, ear length and ear diameter these three characters had the least contribution towards divergence among the 20 short statured maize inbred lines. In vector I (the major axis of differentiation) other characters responsible for genetic divergence were ear height and thousand grain weight showed negative vector values and in vector II (the second axis of differentiation) they showed positive vector values. It was supported by several authors such as [
Among the 20 short-statured inbreds, the performance of inbred lines 16 and 13 showed high yield with different yield contributing traits. Plant and ear height was found the highest in inbred line18 followed by 19 and 09 and it was found lowest in 05 followed by 07 and 17. Plant height ranged from 49.30 cm to 122.30 cm and ear height ranged from 12.7 cm to 47.0 cm. In all the lines, ear placement was at or near the midpoint of the plant which was a desirable character. In cluster analysis maximum of 07 short-statured inbred lines were included in cluster III followed by 06 in cluster IV. These two clusters contained 65% of the total inbred lines. The inter-cluster distance was maximum between cluster II and V (28.19) followed by cluster II and IV (24.62) and then between cluster I and IV (19.72). While the inter-cluster distance was minimum between cluster I and III (9.18) followed by cluster IV and V (9.65) and then between cluster II and III (12.09). Cluster II and III gave the lowest mean for plant and ear height. The highest cluster mean for some desired yield contributing characteristics were observed in cluster I, II, IV and V, second highest value of some desired character recorded in cluster III, IV. Both the vectors I and II had positive values for yield per plant, days to silking, plant height, rows per cob, seeds per row indicated that these five characters had the highest contribution and had negative value for the date of tasseling, ear length and ear diameter indicated that these three characters had the lowest contribution towards the divergence among 20 inbred lines.
Out of twenty inbreds, seven short statured maize inbred lines such as SP05, SP06, SP03, SP04, SP02, SP01, SP07 were selected for crossing and evaluation considering overall performance, yield performance, cluster distance, cluster mean and contribution of the characters towards divergence.
There were no conflicts of interests.
Billah, M.M., Hassan, L., Matin, M.Q.I., Talukder, M.Z.A. and Alam, M.K. (2021) Genetic Diversity for Yield and Yield Contributing Characters of Short Statured Maize Inbred Lines. American Journal of Plant Sciences, 12, 934-945. https://doi.org/10.4236/ajps.2021.126063