Floral biology and pollen germination studies in China aster [Callistephus chinensis (L.) Nees]

An investigation on ‘floral biology and pollen germination in China aster [Callistephus chinensis (L.) Nees.] was carried out during two consecutive years 2020-2022. Results revealed that anthesis was observed in afternoon hours from 2:15 p.m.-3:15 p.m. in China aster genotype Arka Aadya, whereas, in Arka Archana, Arka Kamini and Arka Poornima, it was 10:15 a.m. to 11:30 a.m. Among genotypes, anther dehiscence was observed from forenoon till afternoon. Number of ray florets per flower head ranged from 29.53 (Arka Shashank) to 132.37 (Arka Poornima), while, disc florets per flower head ranged from 128.93 (Arka Shashank) to 238.93 (Arka Poornima). Hundred per cent pollen viability was recorded in Arka Aadya, Arka Archana, Arka Kamini, and Arka Shashank. Seed set was ranged from 24.55% (Arka Poornima) to 54.13% (Arka Kamini). Increased stigma receptivity among the genotypes was observed from bud stage to fully expand floret stage and declined in semi expanded tubular disc stage. Among genotypes, maximum pollen germination was observed in Arka Archana (17.67%) followed by Arka Kamini (14.10 %). Among different media, maximum pollen germination ranged from 5.13% (10% sucrose + 15% PEG +BK medium) to 17.07% (10% sucrose + 15% PEG + BK media). Among interaction effect, maximum pollen germination was recorded in 15% sucrose + 30% PEG +BK medium x Arka Kamini (70.50%) followed by 10% sucrose +15% PEG +BK medium x Arka Archana (44.33%) and 10% sucrose +15% PEG +BK medium x Arka Aadya (44.00%).