Formation of sunflower seeds via pollination methodology comparison revealed by self incompatibility

Background and Objective: Sunflowers have capitula that are hermaphrodite but protandry that causes self-incompatibility, which is an inability of plants to form seeds because the stamens occur before the pistil. This research aimed to understand the effect on the formation of sunflower seeds by comparing five pollination methods revealed by their self-incompatibility. Materials and Methods: The study had been conducted in Malang, East Java, Indonesia, from May until October, 2019 by using four genotypes, namely HA10, HA11, HA45, HA50 as the female parents and HA12 as the male parent. The genotypes were grown in field conditions. Several traits were observed after the genotypes being pollinated and the data were analyzed by analysis of variance (ANOVA). Results: The pollination method affected the flower head diameter, age of stamens and pistil occurrences, 100 seed weight, number of unfilled and filled seeds, the total number of seeds and seed set percentage but did not affect the flower head weight. On the other hand, genotype treatment affected the flower head weight, age of stamens and pistil occurrences, 100 seed weight and the number of filled seeds. Self-incompatibility criteria are strongly influenced by the successful seed formation that was obtained from the character of seed set percentage. Conclusion: The seed set percentages show that each pollination method's self-incompatibility criteria are high self-incompatibility for natural self-pollination, low self-incompatibility for manipulated self-pollination, cross-pollination, manipulated cross-pollination and very low self-incompatibility for open pollination. The four sunflower genotypes have the same criteria that are low self-incompatibility