GENETIC VARIATION IN SOURCE-SINK RELATED TRAITS IN WHEAT (Triticum aestivum L.)

Abstract

Characterization of 10 popular winter wheat varieties released by BAR!was done by studying variability, heritability, correlation and path co-efficient analysis. Source sink relationship was the main focus, so all the varieties were evaluated for source characters such as dry weight of green leaf, dry weight of stem and leaf sheath at 50% booting stage, tiller number per square meter, LAI, LAR, vegetative period and grain filling period. Side by side, sink characters like dry weight of particle at 50% booting stage, number of grains per spike. 1000 grain weight and grain yield per sq. meter were also studied. The experiment was conducted in randomized block design with three replications in the cxperimcntal field of Shcr-e-l3angla Agricultural University during the wheat growing season of 2012-2013. Significant variations were observed among all the varieties for all the character studied. The variety Gourav, Sonalika, BARI-26. BARI-25 and BARI-23 showed higher yield. The highest genotypic and phenotypic coefficient of variation was observed for dry weight of green leaf and dry weight of stem and leaf sheath at 50% booting stage. Vegetative period showed the lowest estimation of variation. All the characters were highly heritable, among them dry weight of panicle. leaf area ratio, total dry matter and grain yield coincided high genetic advance (5%). Leaf area ratio, total dry matter and dry weight of leaf sheath at 50% booting stage coherently showed high genetic advance (% mean) but grain yield did not. Correlation study indicated that grain yield had significant positive genotypic relation with dry weight of panicic at 50% booting stage and 1000 grain weight. In connasc, leaf area ratio at 50% booting stage showed significant negative relation with grain yield. Through path coefficient analysis it was thrther evident that, number of tillers per sq. meter had the highest direct positive effect on yield but due to indircct negative effect of LAID (Leaf Area Index at 50% Booting stage), LAR13 (Leaf Area Ratio at 50% Booting stage) and grain filling period on this trait, the correlation became positive but very weak. In coherence of the highest negative correlation coefficient, Leaf area ratio at 50% booting stage exerted the highest direct negative effect on yield. Thousand grain weight and number of grain per spike contributed to yield by both direct and indirect means.