Indian mustard ( Brassica juncea L.) germplasm consisting 167 accessions including one check cultivar was evaluated for qualitative and quantitative traits. The present study was conducted to investigate genetic diversity and correlation among studied genotypes of B. juncea L. based on agro-morphological at NARC, Islamabad, Pakistan. To investigate the genetic diversity based on morphological characters, data was recorded on 20 quantitative and 12 qualitative traits. The calculated data was analyzed through two complementary methods, i.e. PCA (Principal Component Analysis) and cluster analysis. Among all the studied cultivars, significant diversity was recorded for different agro-morphological characters. Among all the parameters, maximum variance was recorded for pod shattering (427.2) followed by plant height (345.6), days to 100% flowering (336.2) and main raceme length (210.0). Among all the characters, the greatest and highly significant association (0.99) was found between days to maturity 50% and days to maturity 100% followed by correlation (0.86) among days to flowering 50% and days to flowering 100%, correlation value (0.71) was calculated among leaf length and leaf width. Using cluster analysis all the genotypes were divided into five major groups. It was observed that 7 out of 20 principal components with an Eigen value of ≥1.0 calculated for 73.92% of the total diversity observed between 167 accessions of Indian mustard ( B. juncea L.). The contribution of first three PCs in the total PCs was 23.25, 12.87 and 11.24, respectively. Among all the investigated accessions two genotypes 26,813 and 26,817 showed great potential for seeds/silique, 1000-seed weight and seed yield/plant, respectively, so these genotypes are recommended for future breeding programs for achieving promising results.
Brassica juncea L. commonly known as Indian mustard is globally used as oilseed, vegetable and condiments. The crop species is said to be one of the earliest domesticated species. B. juncea annually grows as wild and cultivated species over a large geographical range, across the Asia, Africa, Australia, America and Europe [
So for the prosperity of the country, it is essential to increase the production of these crops and for maximum production, exploitation of genetic diversity of these crops is essential. Pakistan being an agricultural country but unfortunately it is deficient in the oilseed production and a large amount ($ 1054.7 million) is spent on the import about 77% of edible oil. After petroleum, Pakistan pays the second largest import bill for edible oil among food items [
Diversity can be determined by three different levels, first one is genetic diversity, in which the variation observed at gene and germplasm level, the second one is diversity of species, in which richness of species at a specific location and the third one is the Eco-system diversity, in which crop species interact with their environment. Diversity is potent for different crops to fulfill the gap between demand and production across the world [
Plant material comprises 167 germplasm including 1 check cultivar of B. juncea L. for estimation of agro-morphological variation. The germplasm were provided by PGRI gene-bank, NARC, Islamabad, Pakistan. The present research work was conducted in the experimental area of NARC (33˚43'N and 73˚06'E) during the year 2012-2013 using augmented design. The average annual rainfall in this area ranges from 500 - 900 mm with 70% in summer and 30% in winter. Row to row distance of 70 cm was maintained with one accession per row and the length of the row was 2.5 meter for each and every accession and genotype. During seed bed preparation the field was irrigated before sowing to provide conditions of optimum moisture while afterword no irrigations were given and the crop was grown under rain-fed conditions. The experimental germplasm were planted at a depth of 3 - 4 cm using hand drill. After germination to maintain proper plant population thinning was carried out by hand. After 30 days of germination weeding was carried out and because of no serious attack of insect pest no insecticides and pesticides were sprayed throughout the plant growth stage. The crop was harvested when almost more than 75% of plants were turned yellowish in color. Data were recorded for twenty quantitative traits such as Days to 50% flowering, Days to 100% flowering, Days to 50% maturity, Days to 100% maturity, Leaf length, Leaf width, Leaf width/leaf length ratio, Leaves per plant, Plant height, Primary branches per plant, Main raceme length, Silique per main raceme, Silique length, Silique width, Silique length and silique width ratio, Stem thickness, Seed per silique, 1000-seed weight, Seed yield per plant, Shattering percentage (%). The description of calculating different parameters is given in
During the present research work days to 50% flowering exhibited highly significant positive correlation with the parameter i.e. days to 100% flowering (0.86**), leaf length (0.28**) and leaves per plant (0.21**), similarly days to 50% flowering, had significant positive correlation with days to maturity 100% and leaf length/leaf width ratio (0.18*), plant height (0.17*), days to maturity 50%, leaf width and primary branches per plant (0.16*). While days to flowering 50% had significant negative correlation was observed with silique width (−0.18*). Days to 100% flowering had highly positive significant correlation with leaf length (0.37**), days to maturity 100% (0.29**), days to maturity 50%, leaves per plant and stem thickness (0.27**) and primary branches per plant (0.24**). While the trait like plant height (0.19*) and leaf width (0.18*) had found significant positive correlation with days to 100% flowering (
Characters | Range | Description |
---|---|---|
Days to Flowering 50% | <80 80 - 90 91 - 100 101 - 110 >110 | Early Medium Average Late Very Late |
Days to Flowering 100% | <90 90 - 105 106 - 115 116 - 130 >130 | Early Medium Average Late Very Late |
Days to Maturity 50% | <140 140 - 150 151 - 160 161 - 170 171 - 180 | Early Medium Average Late Very Late |
Days to Maturity 100% | <150 150 - 165 166 - 180 181 - 195 196 - 210 | Early Medium Average Late Extreme Late |
Leaf Length (cm) | <5.0 5.1 - 15.0 15.1 - 25.0 25.1 - 35.0 | Small Medium Large Extra-Large |
Leaf Width (cm) | <5.0 5.1 - 10.0 10.1 - 15.0 15.1 - 20.0 | Small Medium Average Large |
Leaf Length/ Leaf Width Ratio | 0.8 - 2.0 2.1 - 3.0 3.1 - 4.0 >4.0 | Small Medium Average Large |
Leaves Per Plant | 9.0 - 12.0 12.1 - 16.0 16.1 - 20.0 20.1 - 24.0 | Minimum Medium High Maximum |
Stem Thickness (mm) | <15.0 15.0 - 20.0 20.1 - 25.0 >25.0 | Thin Average Thick Highly thick |
Plant Height (cm) | <120.0 120.0 - 140.0 140.1 - 160 160.1 - 180.0 >180.0 | Dwarf Medium Average Tall Taller |
---|---|---|
Primary Branches Per Plant | <5.0 5.0 - 10.0 10.1 - 15.0 >15.0 | Minimum Medium High Maximum |
Main Raceme Length (cm) | <20.0 20.0 - 40.0 40.1 - 60.0 60.0 - 80.0 | Short Medium Large Very Large |
Siliquae Per Main Raceme | <20 20.0 - 40.0 40.1 - 60.0 60.1 - 80.0 >80.0 | Less Less than Average Average More than Average Highest |
Silique Length (mm) | <35.0 35.0 - 45.0 45.1 - 55.0 >55.0 | Very Short Short Average Maximum |
Silique Width (mm) | <4.0 4.0 - 5.0 >5.0 | Thin Greater Maximum Thickness |
Silique Length/Silique Width Ratio | <10.0 10.0 - 12.0 >12.0 | Small Average Large |
Seed Per Silique | <15.0 15.0 - 20.0 >20.0 | Minimum Average Maximum |
1000-Seed Weight (g) | <4.0 4.0 - 8.0 >8.0 | Minimum Average Maximum |
Seed Yield Per Plant (g) | <5.0 5.0 - 10.0 10.1 - 15.0 >15.0 | Minimum Average More than Average Maximum Yield |
Shattering % | <20 20.0 - 40.0 40.1 - 60.0 60.1 - 80.0 >80.0 | High Resistant Low Resistance Medium Shattering High Shattering Extreme Resistance |
Trait | DF50 | DF100 | DM50 | DM100 | LL | LW | LL/LW | L/P | ST | PH | PB/P | MRL | S/MR | SL | SW | SL/SW | S/S | TSW | SY/P | SH |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
DF50 | 1 | |||||||||||||||||||
DF100 | 0.86** | 1 | ||||||||||||||||||
DM50 | 0.16* | 0.27** | 1 | |||||||||||||||||
DM100 | 0.18* | 0.29** | 0.99** | 1 | ||||||||||||||||
LL | 0.28** | 0.37* | 0.30** | 0.31** | 1 | |||||||||||||||
LW | 0.16* | 0.18* | 0.12 | 0.12 | 0.71** | 1 | ||||||||||||||
LL/LW | 0.18* | 0.22** | 0.21** | 0.24** | 0.27** | −0.41** | 1 | |||||||||||||
L/P | 0.21** | 0.27** | 0.20** | 0.19* | 0.49** | 0.37** | 0.15* | 1 | ||||||||||||
ST | 0.12 | 0.27** | 0.42** | 0.43** | 0.29** | 0.30** | −0.1 | 0.41** | 1 | |||||||||||
PH | 0.17* | 0.19* | 0.06 | 0.05 | 0.29** | 0.47** | −0.33** | 0.36** | 0.45** | 1 | ||||||||||
PB/P | 0.16* | 0.24** | 0.30v | 0.28** | 0.44** | 0.50** | −0.1 | 0.41** | 0.43** | 0.46** | 1 | |||||||||
MRL | 0.02 | 0.05 | 0.08 | 0.05 | 0.15* | 0.18* | −0.17* | 0.20** | 0.14 | 0.38** | 0.26** | 1 | ||||||||
S/MR | 0.11 | 0.14 | 0.40** | 0.38** | 0.40** | 0.27** | 0.05 | 0.30** | 0.22** | 0.32** | 0.31** | 0.59** | 1 | |||||||
SL | −0.06 | −0.08 | 0.14 | 0.16* | −0.04 | −0.08 | 0.03 | −0.13 | −0.09 | −0.19* | 0.07 | −0.08 | −0.09 | 1 | ||||||
SW | −0.18* | −0.12 | 0.18* | 0.19* | 0.05 | 0.02 | 0.02 | 0.1 | 0.08 | −0.1 | 0.06 | 0.08 | 0.15 | 0.16* | 1 | |||||
SL/SW | 0.13 | 0.05 | −0.08 | −0.08 | −0.08 | −0.07 | −0 | −0.18* | −0.12 | −0.03 | 0 | −0.12 | −0.18* | 0.50** | −0.75** | 1 | ||||
S/S | −0.06 | −0.07 | 0.29** | 0.30** | 0.20** | 0.04 | 0.23** | 0.03 | −0.1 | −0.14 | 0.01 | −0.04 | 0.18* | 0.02 | 0.26** | −0.25** | 1 | |||
TSW | 0.03 | 0 | 0.18* | 0.18* | 0.03 | −0.02 | 0.1 | 0 | 0.03 | 0.03 | 0.07 | 0.15 | 0.22** | −0.06 | 0.19* | −0.21** | 0.16** | 1 | ||
SY/P | 0.07 | 0.11 | 0.42** | 0.41** | −0.02 | −0.11 | 0.15* | 0.1 | 0.20** | 0 | 0.09 | −0.07 | 0.05 | 0.08 | 0.06 | 0.02 | 0.1 | 0.06 | 1 | |
SH | −0.02 | −0.08 | −0.35** | −0.37** | −0.32** | −0.18* | −0.18* | −0.26** | −0.12 | −0.17* | −0.21** | −0.23** | −0.43** | 0 | −0.1 | 0.09 | −0.31** | −0.1 | −0 | 1 |
Note: *significant at 0.05 (0.15 to 0.19 value); **highly significant at 0.20 & above probability level (more than 0.00 level); The green, yellow, white, red colors shows strong positive, weak positive, moderate positive, and strong negative correlations among different traits respectively.
Principal component analysis (PCA) was carried out based on twenty quantitative morphological characters. The 7 principal components account for 73.92% of the overall variability among the studied B. juncea L. accessions for the total phenotypic variations (
The contribution of PC-II in total differences was 12.87% and was positively associated with days to maturity 50 and 100% (0.520 and 0.540), leaf length/ width ratio (0.540), silique on main raceme (0.034), silique length (0.234), silique width (0.435), seed per silique (0.530), 1000-seed weight (0.270) and seed yield per plant (0.394), whereas days to flowering 50 and 100% (−0.176 and −0.133), leaf length (−0.149), leaf width (−0.506), leaves per plant (−0.187), stem thickness (−0.153), plant height (−0.580), primary branches per plant (−0.280), main raceme length (−0.243), silique length/width ratio (−0.245) and shattering percentage (−0.215) were negative associated with PC-II.
PC-III showed 11.24% of the total agro-morphological variation and positively associated with leaf width (0.161), leaves per plant (0.033), plant height (0.144), primary branches per plant (−0.015), main raceme length (0.365), siliqua per main raceme (0.266), seeds per silique (0.205), 1000-seed weight (0.232) and silique width (0.578), while negatively associated with days to flowering 50%
PC1 | PC2 | PC3 | PC4 | PC5 | PC6 | PC7 | |
---|---|---|---|---|---|---|---|
Eigen value | 4.67 | 2.57 | 2.25 | 1.61 | 1.38 | 1.27 | 1.03 |
Cumulative Eigen value | 4.67 | 7.24 | 9.49 | 11.11 | 12.48 | 13.75 | 14.78 |
Percent Variance | 23.35 | 12.87 | 11.24 | 8.07 | 6.89 | 6.35 | 5.15 |
Cumulative Variance | 23.35 | 36.22 | 47.46 | 55.54 | 62.42 | 68.77 | 73.92 |
Traits | Eigenvectors | ||||||
Days to Flowering (50%) | −0.385 | −0.176 | −0.610 | −0.463 | −0.054 | 0.138 | −0.309 |
Days to Flowering (100%) | −0.494 | −0.133 | −0.587 | −0.443 | −0.135 | 0.095 | −0.251 |
Days to Maturity (50%) | −0.680 | 0.520 | −0.183 | 0.273 | −0.151 | 0.063 | 0.022 |
Days to Maturity (100%) | −0.679 | 0.540 | −0.207 | 0.252 | −0.147 | 0.037 | 0.016 |
Leaf Length | −0.711 | −0.149 | −0.066 | −0.186 | 0.329 | −0.396 | 0.004 |
Leaf Width | −0.569 | −0.506 | 0.161 | 0.093 | 0.103 | −0.417 | −0.107 |
Leaf Length/Width Ratio | −0.112 | 0.540 | −0.353 | −0.423 | 0.274 | −0.021 | 0.192 |
Leaves/Plant | −0.616 | −0.187 | 0.033 | −0.180 | −0.026 | −0.196 | 0.228 |
Stem Thickness | −0.606 | −0.153 | −0.029 | 0.193 | −0.492 | −0.025 | 0.165 |
Plant Height | −0.513 | −0.580 | 0.144 | 0.133 | −0.118 | 0.155 | 0.106 |
Primary Branches/Plant | −0.645 | −0.280 | 0.015 | 0.243 | −0.033 | −0.160 | −0.116 |
Main Raceme Length | −0.391 | −0.243 | 0.365 | 0.095 | 0.246 | 0.563 | −0.143 |
Siliqua/Main Raceme | −0.653 | 0.034 | 0.266 | 0.040 | 0.319 | 0.394 | −0.030 |
Silique Length | 0.073 | 0.234 | −0.290 | 0.592 | 0.228 | −0.224 | −0.509 |
Silique Width | −0.193 | 0.435 | 0.578 | −0.108 | −0.253 | −0.259 | −0.414 |
Silique Length/Width Ratio | 0.224 | −0.245 | −0.696 | 0.490 | 0.349 | 0.090 | 0.022 |
Seeds/Silique | −0.230 | 0.530 | 0.205 | −0.103 | 0.332 | −0.238 | 0.059 |
1000-Seed Weight | −0.203 | 0.270 | 0.232 | −0.116 | −0.007 | 0.378 | −0.338 |
Seed Yield/Plant | −0.251 | 0.394 | −0.248 | 0.236 | −0.388 | 0.125 | 0.248 |
Shattering (%) | 0.506 | −0.215 | −0.119 | −0.069 | −0.445 | −0.069 | −0.295 |
and 100% (−0.610 and −0.587), days to maturity 50% and 100% (−0.183 and −0.207), leaf length (−0.066), leaf length/leaf width ratio (−0.353), stem thickness (−0.029), silique length (−0.290), silique length/width ratio (−0.696), seed yield per plant (−0.248) and shattering percentage (−0.119).
The PC-IV contributed 8.07% in the total variability and were positively contributed to days to maturity 50% and 100% (0.273 and 0.252), leaf width (0.093), stem thickness (0.193), plant height (0.133), primary branches per plant (0.243), main raceme length (0.095), silique per main raceme (0.040), silique length (0.592), silique length/width ratio (0.490) and seed yield per plant (0.236). Similarly the traits i.e. days to flowering 50% and 100% (−0.463 and −0.443), leaf length (−0.186), leaf length/width ratio (−0.423), leaves per plant (−0.180), silique width (−0.108), seed per silique (−0.103), 1000-seed weight (−0.116) and shattering percentage (−0.069) contributed negatively.
In the total variability the contribution of PC-V was observed 6.89% and the parameter i.e. leaf length (0.329), leaf width (0.103), leaf length/width ratio (0.274), main raceme length (0.246), siliqua per main raceme (0.319), silique length (0.228), silique length/width ratio (0.349), seeds per silique (0.332) were positively contributed. Whereas the characters i.e. days to flowering 50 and 100% (−0.054 and −0.135), days to maturity 50% and 100% (−0.151 and −0.147), leaves per plant (−0.026), stem thickness (−0.492), plant height (−0.118), primary branches per plant (−0.033), silique width (−0.253), 1000-seed weight (−0.007), seed yield per plant and shattering percentage (−0.388 and −0.445) contributed negatively.
The PC-VI depicted proportion of variability as 6.35% and were positively associated with days to flowering 50% and 100% (0.138 and 0.095), days to maturity 50 and 100% (0.063 and 0.037), plant height (0.155), main raceme length (0.563), siliqua per main raceme (0.394), silique length/width ratio (0.090), 1000-seed weight (0.378), and seed yield per plant (0.125). Similarly the traits i.e. leaf length (−0.396), leaf width (−0.417), leaf length/width ratio (−0.021), leaves per plant (−0.196), stem thickness (−0.025), primary branches per plant (−0.160), silique length (−0.224), silique width (−0.259), seeds per silique (−0.238) and shattering percentage (−0.069) were negatively associated with PC-VI.
PC-VII accounted 5.15% of the total variation among agro-morphological traits. Days to maturity 50% and 100% (0.022 and 0.016), leaf length (0.004), leaf length/width ratio (0.192), leaves per plant (0.228), stem thickness (0.165), plant height (0.106), silique length/width ratio (0.022), seeds per silique (0.059) and seed yield per plant (0.248) were contributed positively to PC-VII. Whereas days to flowering 50% and 100% (−0.309 and −0.251), leaf width (−0.107), primary branches per plant (−0.116), main raceme length (−0.143), siliqua per main raceme length (−0.030), silique length (−0.509), silique width (−0.414), 1000-seed weight (−0.338) and shattering percentage (−0.295) depicted negative contribution.
Maximum variation was calculated for shattering (427.2) followed by plant height (345.6), days to flowering 100% (336.2), main raceme length (210.0), days to flowering 50% (185.1), days to maturity 100% (122.9), days to maturity 50% (83.8). The results obtained from the present investigation were in closed agreement with that of [
Our results were strengthened by many earlier plant breeders and scientists. The highly significant and positive correlation was observed between the parameters of days to flowering 50% and 100% and days to maturity 50% and 100% physiological maturity. These results were supported by the results of Nasim et al. [
Numerous plant breeders and plant scientist in the earlier era had practiced and got remarkable results of diversity in agro-morphological parameters for various Brassica individuals through two complementary methods i.e. cluster analysis and principal component analysis (PCA). These techniques were successfully observed in Indian mustard (Brassica juncea L.) germplasm by Gupta et al. [
Among all the characters, valuable genetic diversity was observed through different agro-morphological traits i.e. days to maturity 50% and days to maturity 100%, days to 50% flowering and days to flowering 100%, leaf length and leaf width, main raceme length siliquae per main raceme, leaf width, primary branches per plant, silique length. Most of the traits contributed highly significant association for the said trait during the present investigation. These genotypes show that there is great potential in the studied accessions, which can be used in future breeding program as a productive genotypes.
We acknowledge cooperation of Gene bank of PGRI, NARC, Islamabad, Pakistan for providing B. juncea germplasm.
The author’s declares that there is no conflict of interests regarding the publication of this article.
Saleem, N., Jan, S.A., Atif, M.J., Khurshid, H., Khan, S.A., Abdullah, M., Jahanzaib, M., Ahmed, H., Ullah, S.F., Iqbal, A., Naqi, S., Ilyas, M., Ali1, N. and Rabbani, M.A. (2017) Multivariate Based Variability within Diverse Indian Mustard (Brassica juncea L.) Genotypes. Open Journal of Genetics, 7, 69-83. https://doi.org/10.4236/ojgen.2017.72007