Strategies for pollen harvest and storage for increasing pollination and yield in hybrid rice seed production of Mestiso 19 cultivar

Abstract

Attainment of high seed yield in hybrid rice seed production is a function of the amount of pollen that the male parent can shed during pollination. Low pollen load of the male parent (TG101M) of hybrid rice, Mestiso 19 leads to low seed yield which limits the number of hybrid rice seed growers engaged in its hybrid seed production. Artificial pollination, through collection and storage of sufficient amount of pollen may provide a solution to the problem. Additional pollen artificially loaded onto stigmas of female parent of Mestiso 19 (PRUPTG101) may increase seed yield. The study was conducted during wet and dry season of year 2016 and 2017 at Phil Rice Central Experiment Station to develop technique in pollen collection and storage of TG101M. Pollens were collected at anthesis, 30 minutes and 1 hour after anthesis, then stored in amber glass, paper and ziplock plastics and stored for 24, 48 and 72 hours in 280C, 50C, -50C. Pollens were grown in three different media for pollen viability and germination and viewed under the microscope for pollen tube growth. Pollen viability and germination was high at anthesis and decreased thereafter. Pollen grains grown in media 2 maintained pollen viability even after 1 hour after anthesis. Pollen germination decreased over time regardless of media used. Pollen tube length was consistently high at anthesis when pollen grains were grown in media 2 and 3 only.  The length of pollen tube growth from medium 2 differed between 30 min and 1 hour. Less than 50% viable pollen was achieved after 24 hours of storage. Pollen viability and germination decreased beyond 24 hours. To increase the viability of collected pollen from TG101M for possible artificial pollination, grains must be collected at anthesis and stored immediately in amber glass under cold storage at negative 5°C.