Abstract:
World climate change requires urgent policies from the government as well as private sector in order to cope its effects on world agriculture. People involved with agriculture are more prone to this climate change as more widespread temperature extremes with unpredictable rainfall patterns causes a great loss to their crops and economies. In Pakistan, grain yield of wheat is low as it is comparatively more affected by various biotic and abiotic stresses. Amid abiotic stresses, late sowing is most important reasons for limiting wheat production in Pakistan. Development of new wheat genotypes suitable for normal and late planting is one of the foremost objective of wheat breeding programs. Present investigations were done at research area of Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad. Means of the six populations i.e.: P1, P2, F1, F2, BC1 and BC2 of the 3 bread wheat crosses; (1) Aas 2011 × Lasani 2008 (2) Miraj 2008 × Punjab 2011 and (3) Bhakkar 2002 × Sehar 2006 were used to estimate genetic parameters through generation mean analysis under normal and late sowing conditions. Data was taken for the following traits viz; plant height, flag leaf area, spike length, number of tillers plant-1, peduncle length, grains number spike-1, number of spikelets spike-1, grain weight spike-1, grain yield plant-1, days to heading, days to maturity, grain filling rate, 1000 grain weight, grain filling duration and harvest index. Highly significant difference depicted by analysis of variance among parents and their generations under both sowing conditions. Generation mean analysis showed that epistatic gene effect cannot be ignored when establishing a new breeding program to improve wheat populations for late sown environment. The inheritance of all traits studied was controlled by both additive and non-additive genetic effects, with greater values of additive gene effect than the dominant one in most cases. Heritability estimates were found moderate to high. Significant positive correlation of grain weight per spike, number of grains per spike, grain filling duration, number of tillers per plant, number of spikelets per spike with grain yield per plant was observed. Grain yield per plant was observed most sensitive in cross 1 (Aas 2011 × Lasani 2008). Over all cross 2 (Miraj 2008 × Punjab 2011) has performed better in late sowing conditions.
