Studies on genetic diversity and character association analysis in bread wheat (Triticum aestivum L. em.Thell)
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Date
2020-12
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Wheat (Triticum aestivum L. em. Thell), also known as Bread Wheat is an allohexaploid crop (2n=6x=42), belongs to family Gramineae. It is known as ‘King of Cereals’ as it is the best staple diet for the people and can be grown in variety of soils and climates. It is also a crop where conventional plant breeding has paid rich dividend as epitomized by the Green Revolution. The present investigation was conducted at N. E. Borlaug Crop Research Centre, G. B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand; during the Rabi Season 2019-20. The experiment was carried out in the Augmented Block Design containing 90 test entries, along with 3 checks Sonalika, HD 2967 and HI 8713. There were 3 blocks, each containing 30 test entries along with their 3 checks (randomly allocated). The observation were recorded for seven characters viz; days to 75% heading, plant height, number of tillers per meter, 1000- grain weight, spike length, number of grains per spike and grain yield per plot. The recorded data were analysed fir analysis for variance, variability, heritability, genetic advance, correlation and clustering of different genotypes. Results revealed that variance was highest for grain yield per plot and lowest for spike length. The coefficient of variability was recorded highest for grain yield and lowest for days to 75% heading. Highest heritability was recorded for tillers per meter and lowest for 1000- grain weight. Grain yield exhibited highest genetic advance in percent of mean and lowest for days to 75% heading. However, with respect to correlation with one or other traits, grain yield was positively and significantly correlated with days to 75% heading, plant height, tillers per meter, grain per spikelet, spike length and grain yield per plot. Path coefficient revealed that 1000- grain weight exerted positive effect on all characters except days to 75% heading. The genotypes were classified into 7 different cluster by Non- Hierarchical Euclidean Cluster Analysis. Cluster -I had 13 genotypes whereas cluster -II had 20 genotypes, cluster- III had 8 genotypes, cluster -IV had 12 genotypes, cluster -V had 9 genotypes, cluster-VI has 15 genotypes and cluster-VII had genotypes 16 genotypes. The maximum intra cluster distance was found for cluster-IV (2.096) and cluster-I (1.532) had minimum intra cluster distance. Inter cluster distance was found maximum between cluster –III and cluster –IV (4.166) and minimum was found in cluster –I and cluster –II (2.076). The higher inter cluster distance indicated greater genetic diversity between the genotypes of those clusters, while lower values between the clusters suggested that the genotypes of these clusters had lesser genetic diversity.