Development of drought‐tolerant breeding lines derived from Helianthus annuus × H. argophyllus interspecific crosses

Abstract

Helianthus argophyllus is a wild species known as “silver sunflower”, which possesses several traits, including morphological traits that increase drought tolerance. Therefore, introgressions between chosen cultivated lines and two H. argophyllus accessions were made, and segregating generations were established. Important agronomic traits including single heading, high pollen fertility, silver canopy (indicating more cuticular wax), and content of cuticular waxes and oil were selected over six segregating generations. The resulting F6 lines showed introgression of water saving traits, as they had lower excise leaf water loss, with comparable yield to standard checks. However, these F6 lines were late maturing and showed poor flowering synchronization between the cultivated and introgressed lines. Introgressed line “D‐22” was particularly promising as a breeding line, with superior agronomic and drought resistance traits. This line had the potential to be used as an inbred parental line for introgression of drought resistance traits into elite sunflower germplasm. Combining ability analysis of the introgressed lines further showed their potential for heterosis breeding or to be used as parental lines in breeding programme.

Development of a robust hydroponic method for screening of sunflower (Helianthus annuus L.) accessions for tolerance to heat and osmotic stress

“…However, the present study has shown that gravel may affect the pH and was replaced by glass balls. Screened traits, such as cuticular waxes and root length, act as a buffer against yield reduction under drought and heat stress conditions and consequently increases WUE 8,13 . Resistant hybrids had higher yields over susceptible hybrids during spring, which coincides with the reproductive phase and heat stress.…”

“…can modulate synergistic impacts; for instance, osmotic stress can increase injury in the presence of heat stress 1 . Empirical plant breeding programs address the issue over simplistically as individual abiotic factors 8 . For this reason, artificially bred varieties are most likely to fail to cope with multiple abiotic stresses under field conditions 9 .…”

“…The occurrence of both stresses increases injury and causes greater yield losses 7 . This physiologic change is associated with osmotic stress that results in increased plant injury 8 . Therefore, irrigation is used to ameliorate the hydric stress effects, consequently increasing the production cost where water is scarce.…”

Transcriptomic basis for salt tolerance and disease resistance of silverleaf sunflower revealed by Iso-seq and RNA-seq

“…As for H. argophyllus, there is 83% of the chromosomes showing collinearity with the reference genome, and the percentage is even lower for H. niveus (64%) [7]. In concert to the genetic variation, the phenotypes, such as seed dormancy, flowering time, oil composition and content, as well as the resistance to abiotic and biotic resistance, also vary substantially across genotypes [19,41,42]. Therefore, to better understand the mechanisms and genomic resources underlying those desirable traits observed in the wild species, a reference genome, or at least a reference transcriptome, is needed for each valuable genotype.…”

“…Among them, silverleaf sunflower (H. argophyllus),, a sister species of H. annuus, is one of the most important donors. For example, it has been used as a donor of alleles for disease resistance [10][11][12][13][14][15][16][17] and drought tolerance [18,19]. Overall, it is the largest donor of genes to the cultivated sunflower, with approximately 5% of the genes in the cultivated sunflower were introgressed from H. argophyllus.…”