EFFECTS OF NECTAR COMPOSITION AND FLORAL TRAITS ON ONION SEED PRODUCTION

GATICA I.; SOTO V.; GALMARINI C.

Madison

Congreso; International Allium Research Symposium; 2019

ISHS

Onion seed production is an activity that has been notoriously developed in the last decade in Argentina. Honey bees are the main pollinators of onion crops for seed production. Two types of onion varieties are usually grown around the world; open pollinated (OP) and male sterile lines (MSL). Hybrid onions offer numerous advantages to growers, nonetheless, a highly variable seed yields between different hybrid seeds of onion have been observed. Nectar is the most important floral reward offered by plants. Recently we have been studying the correlation of nectar composition, floral traits and seed yield under controlled and open field conditions. Also, we studied the influence of pollen viability in different onion fertile lines on the final yield and quality of onion hybrid seed production. Nectar composition was described through the analysis of sugars, phenol and alkaloid compounds. There were significant differences in the analysed traits among different onion lines. For nectar traits we found a significant influence of the environment where plants were cultivated. Nonetheless, flower traits do no interact with the experimental sites and only the genotype had influence in line differences. There are qualitative and quantitative differences in the chemical composition of nectar and floral traits between OP and MSLs and also within MSLs, and these differences are correlated with bee attraction and seed yield. Thus, it would be possible to select indirectly the most promising productive MSL using simple determinations like some floral morphological characters.There is variation in pollen viability percentage in different fertile lines, nonetheless pollen viability does not influence seed yield, at least for the levels of the evaluated viabilities, and on the other hand higher pollen viability is related with better seed quality. Results will be presented and discussed in the presentation. These data are intended to help seed growers and to provide tools for plant breeders to select MSLs that may produce higher seed yields.