Heterosis expression for agronomic features of sunflower
Author(s) : Mehdi Ghaffari, Farnaz Shariati, Nadia Safavi Fard
Sunflower is an important oil seed crop of world, which is predominately cultivated by hybrid seed. Sunflower breeders continue attempt new cross combinations to develop hybrids with higher manifestation of heterosis. Therefore, present study was conducted with the aim to develop highly heterotic hybrids. The manifestation of heterosis was studied in various phenological and agronomic traits of sunflower. There were 24 single cross hybrids produced by crossing among cytoplasmic male sterile and restorer lines in 2018. Developed crosses were evaluated in 2019 in randomized block design at Karaj, Iran. There was considerable heterosis in desired direction for phenological and agronomic traits which indicated that highly heterotic crosses may be selected to expand yield potential in Iran. Two hybrids R29 × A212 and R19 × A212 with higher seed and oil yield and positive heterosis for these two characteristics were identified as superior hybrids. The results indicated that association of optimum alleles related to flowering time may result in development of early maturing hybrids than related parents. Moreover, heterozgosity may mask recessive alleles, therefore, specific combining ability of parents may be more important than per se performance of inbred parents.The role of maternal effects should be taken into account in breeding of a trait and higher heterosis alone cannot be a reason for the superiority of a hybrid for a particular trait, and ultimate expression of a given feature is more important.