Assessment of pollen morphology and hybridization in pomegranate (Punica granatum)

Pollen studies act as a prerequisite for choosing a compatible pollen parent and help plant breeders to achieve successful crossing between different cultivars. An experiment was conducted during 2018-19 at Fruit Research Farm of Regional Horticulture Research and Training Station Bajaura, Kullu, Himachal Pradesh to evaluate 8 commercial genetically distant pomegranate (Punica granatum L.) cultivars (Chawla, Nabha, P-26, Kandhari Kabuli, G-137, Jodhpur Red, Mridula and Bhagwa) for pollen morphology (shape and size) and viability. Hybridization studies were also carried out to assess the role of cross pollination in fruit set to infuse blood red aril colour and soft seededness in the selected cultivars. The compatibility behaviour was studied by using different cross combinations of cultivars followed by recording their fruit set percentage. It could help breeders understand the performance of cultivars as pollinizers which would ultimately help them in hybridization programs. Pollen viability of the pomegranate germplasm was determined using 2% acetocarmine. Highest pollen viability was recorded in Bhagwa (94.29%) followed by Chawla (91.21%). In hybridization studies, highest fruit set per cent among 16 crosses was observed in Mridula x P-26 (77.80%). The differences in fruit set percentage could be due to varied degree of compatibility between different genotypes, behaviour of pollen with respect to viability percentage, differences in growth rate of pollen tube and might also be due to differences in temperature during bloom period.