Heritability and Combining Ability for Cold Hardiness from Partial Dialleles in Iranian Pomegranate Cultivars

Abstract

The development of cultivars with broader climatic adaptation has recently become the objective of most fruit breeding programmers. Regarding the importance of genetic control of cold hardiness as an influential characteristic for pomegranate and lacking studies in this area, the genetic control of cold hardiness in pomegranate using a partial mating scheme was studied. Five parents, including ‘Rabab Post Ghermez Neyriz’, ‘Malas Yazdi’, ‘Poost Sefid Dezful’, ‘Malas Pishva Varamin’, and ‘Poost Nazok Torosh Abarkuh’ with different cold hardiness capability were screened following a cold hardiness test in the laboratory and an evaluation of cold injury after natural freezing events in the field. The five screened cultivars were crossed in half-diallel crossing scheme with a total of 10 crosses in the Spring of 2014. Cold hardiness of the parent cultivars and the F1 progenies were investigated using the electrolyte leakage (EL) method. Results showed that both general combining ability (GCA) and specific combining ability (SCA) were statistically significant. The hardiest parent (‘Poost Nazok Torosh Abarkuh’) showed the largest positive GCA effect (1560.59) for winter survival, suggesting that this parent is capable to produce tolerant offspring with high breeding values in crossing programs. The significant SCA in this study suggests that specific crosses should be targeted to produce highly capable offspring. Cross between ‘Poost Nazok Torosh Abarkuh’ and ‘Malas Pishva Varamin’ showed high value for SCA (1661.74), indicating capability for production of tolerant offspring to the cold condition. Furthermore, high broad-sense heritability (0.70) and moderate narrow-sense heritability (0.45) for cold hardiness indicate that a reasonable progress could be made in improvement of this trait through conventional breeding.