Effects of nectar composition and floral traits on onion seed production

GALMARINI, C.R.; SOTO, V. C; GATICA HERNÁNDEZ, I; CASELLES, C.; ALBANI, F.

Madison

Simposio; NOA/NARC/IARS Research Conference. Madison, WI, USA. July 2019; 2019

USDA/UW-Madison/NOA

We studied the correlation of nectar composition,floral traits and seed yield of onion under controlled and open fieldconditions, as well as the influence of pollen viability indifferent fertile lines on the final yield and quality of onion hybrid seed. Theexperiments were conducted several years in different locations of the onionseed production area of Argentina. We also studied the influence on bee attraction during pollination and bee?s responses to different onion nectar compounds. Nectar composition was measured by analyses ofsugars, phenol and alkaloid compounds, and there were significant differencesin these traits among onion lines. For nectar traits there was a significantenvironmental influence; however, floral traits differences were influenced bygenotype but did not interact with environments. There were qualitative andquantitative differences in the chemical composition of nectar and floral traitsbetween OP and male-sterile lines (MSLs) and also within MSLs, and thesedifferences were correlated with bee attraction and seed yield. Thus, it shouldbe possible to select more productive MSLs using simple determinations likefloral morphological characters. We also determined that some of the compoundspresent in the onion nectar can improve the bee?s learning performance andtheir retention memory, while others can trigger the opposite effect. Therewas also variation for pollen viability among male-fertile lines, which wasrelated with better seed quality but did not influence seed yield.