Combining xenia, male sterility, and synchronous pollination to improve maize grain yield and market value

Abstract

Xenia (pollination of florets with genetically unrelated pollen), male sterility (removal of fertile pollen), and synchronous pollination (application of pollen when all silks are present) are well-documented processes that influence kernel formation and development in maize. There also have been numerous reports in which xenia and male sterility were combined in an attempt to increase kernel number, kernel weight, and/or grain yield. We present an analysis of published literature exploring impacts of xenia resulting from cross-pollination, male sterility, and synchronous pollination applied individually or in combination. Although synchronous pollination has had the most consistent and positive impact on seed formation, to our knowledge there are no reports combining all three effectors together. Recently developed technology to collect, preserve, and apply large volumes of maize pollen has provided the opportunity to evaluate the cumulative and potentially synergistic effects of synchronous pollination, xenia, and male sterility applied together on maize hybrids. We present the results of a field trial combining all three effectors in maize; this approach increased kernels per ear, kernel oil concentration, and grain yield per hectare. The results suggest synchronous pollination is essential to enable the greatest number of kernels to develop successfully. Male sterility supports kernel formation by providing greater assimilate supply per kernel, and xenia increases sink strength to attract the additional assimilates. The positive response and economic return when these effectors are applied in combination provides a novel opportunity for grain producers to manage kernel formation and composition proactively using pollen to deliver the trait of choice.