Researcher University of Sargodha Sargodha, Punjab, Pakistan
Body of Abstract: Sunflower (Helianthus annuus L.) is an important oilseed crop, but its yield is threatened due to various biotic and abiotic stresses, including drought stress. There is abundant diversity present among related sunflower wild species. To take advantage of this valuable source of phenotypic diversity, a breeding program was initiated to introgress valuable alleles from H. argophyllus into cultivated germplasm and to minimize linkage drag during introgression. The breeding objectives aim to develop drought tolerant breeding lines that show better response to drought and heat stress and accumulate higher biomass under prevailing conditions, Selection for silver canopy traits led to an increase of cuticular waxes, and rejection of plants with low oil content from the selected silver canopy progeny increased the overall oil content of the populations compared to the wild parent and the F1 bringing them closer to acceptable agronomic performance.
The interspecific derived lines (IDL) had 19.4% smaller leaves than the elite cultivated lines (ECL).However, wide variation was observed among the progeny for this trait. IDL were late maturing than ECL (on average, 44% later). ECL were also susceptible to high temeperature, which may have induced earlier flowering. IDL had 22% lower excised leaf water losses (ELWL) than ECL, indicating that this water saving trait was successfully introgressed into the IDL. Moreover, IDL showed significantly (P ≤ 0.05) higher cuticular waxes (141% higher in IDL than ECL). Lines with high GCA are promising in a breeding program due to their capacity to produce superior progeny. . IDL line D-22 showed the highest GCA among all tested inbred lines under non-stress condition. However, B-249 had the highest mean value and positive combining ability under non-stressed conditions. D-22 was the best combiner with the highest head wieght under stressed conditions.