Evaluation of pollen viability, germinability and longevity in Leptochloa crinita accessions

DOMINGUEZ, D.; REMY, M. M.; KOZUB, C.; CAVAGNARO, J. B.; CAVAGNARO, P. F.

Santa Fe

Congreso; XXXIII Argentinian Meeting of Plant Physiology; 2021

Leptochloa crinita is an important native forage grass of arid regions. This strictly-autogamous species reproduces by self-fertilization. For reasons yet unknown, attempting artificial sexual crosses among different L. crinita genotypes has been, so far, unsuccessful. In this work, pollen viability and longevity in 21 L. crinita accessions was evaluated. Pollen was collected from 2-year-old plants, from November to March, during the 2019/2020 season. To this end, inflorescences with most of their flowers in anthesis were collected between 7 and 8 am, and pollen viability was evaluated by staining the pollen grains with acetocarmine glycerol, whereas in-vitro germination was used to examine the germinability of pollen grains. Pollen longevity was determined by evaluating its viability and germinability in increasing time periods from the opening of the anthers (0, 1, 2 and 3 hours). Results revealed high pollen viability (80-90%), which did not decline over time (i.e., polen longevity exceeded 3 hs), for all of the accessions. Pollen germinability was 90% at opening of anthers (time 0), 40-60% after 1 hour, 20-30% after 2 hours, and 0-10% after 3 hours. Altogether, our results suggest that pollen fertility -but not pollen viability or longevity- may be a critical factor when attempting directed sexual crosses in L. crinita breeding programs.