Diversity and consistency of important yield-contributing traits in popular bread wheat (Triticum aestivum) varieties of North-western plains of India

The most popular bread wheat (Trificum aestivum L. emend. Fiori & Paol.) varieties in the major wheat-growing area of India were examined during 1996-97 to 2000-2001 for yield-contributing parameters such as plant height, phenology, grains/m(2) and kernel weight. Per day growth rate in yield accumulation (93-122 kg), grain formation (106145) and grain development (0.74-1.15 mg) was found to vary between varieties, indicating existance of certain amount of genetic diversity between popular varieties for these traits. The varieties 'PBW 343' and 'PBW 373' belonging to timely sown (15-25 November) and late-sown (15-25 December) groups, respectively, possessed good blend of grain number and grain size along with high efficiency during grain-filling phase. Quick ripening and high yield fill rate contributed yield in the popular varieties of this region. Grain weight, grain-formation rate and vegetative phase (%) registered positive contribution in the late-sown varieties, whereas grains/m(2) and grain growth rate were negative contributors in such materials. The late-sown varieties lacked consistency in divergent seasonal conditions.