Genetic components analysis of physiological and agronomic characters of bread wheat genotypes under climate change...

Inappropriate planting time creates conditions that look like the effects of climate change, putting plants under eco-stress. Due to their unpredictable fluctuations, climatic conditions are difficult to control, and therefore the genetic potential of cultivated crops could play a crucial role in this regard. Therefore, the current study attempts to find new wheat genes capable of adapting to climate change to maintain productivity under potential environmental stresses.

Accordingly, six wheat genotypes with distinct agronomic attributes were crossed in a half-diallel model. The genetic components and heritability of antioxidants as well as grain yield for the 6 parents and their fifteen F₁ crosses were evaluated under two sowing dates (normal and late planting).

Findings showed that variance of planting dates was significant or highly significant for all parameters except peroxidase activity, proline, and grain yield. The planting date × genotype associations were discovered to be significant for most of the studied traits. Each additive (D) and dominance (H₁ and H₂) gene effects were significant for most traits under both planting dates, except of additive gene effects for proline, dominance gene effects for spikes number plant^-1, under normal planting date, and grain yield plant^-1 under late planting date, as well as (H₁) for kernels number spike^-1 under normal planting date. All traits were given medium or large values for heritability in the narrow sense (h²_n.s) under each planting date, with the exception of catalase activity under the late planting date, peroxidase activity, proline content under the normal planting date, spikes number plant^-1, kernels weight spike^-1, 1000-kernels weight under late planting date, and nitrogen content under both planting date, which had minimal values of heritability in the narrow sense.

Wheat genotypes, i.e. Sids 14 (P1), Sakha 95 (P3), Misr 3 (P6), P3×P4, P3×P6 and P5×P6 were the best parents and crosses for most of the studied physiological and agronomic traits under late sowing date conditions, and it can be recommended to include these genotypes in the wheat breeding program to withstand climatic changes in late planting. Also, early segregating generations may benefit from selection for these traits since additive gene action plays a key role in shaping them.