Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0011-183X

The tolerance of maize grain yields to abiotic stresses is largely determined by events that occur at or shortly after flowering. Studies were conducted to evaluate ear growth after silking under unstressed conditions or low N environments in two late lowland tropical maize populations, previously selected for tolerance of drought or low N (Tuxpeno Sequia and Across 8328, respectively). Selection under low N or drought reduced florets per ear by 12 and 11 per cycle when evaluated under unstressed conditions. The lag period between pollination and the onset of linear grain growth increased by 1.7 days per cycle in the low N tolerant population grown under unstressed conditions and by 0.6 days per cycle in the drought tolerant population under low N. Selection for tolerance of low N increased biomass per grain at the end of the lag and linear grain filling periods by 40 and 7% per cycle and by 10 and 4% per cycle in the drought tolerant population, across N environments. The duration of linear grain filling declined with selection in the low N tolerant population when grown under unstressed conditions. Selection for tolerance to either stress did not significantly increase grain yield under unstressed conditions, though improvement for drought tolerance increased yield by 7.5% per cycle (P < 0.05) under low N. Selection for tolerance to both stresses increased grains per plant across environments. Apparently, selection for tolerance to low N or drought results in more grains achieving the minimum biomass needed to prevent grain abortion at the onset of the linear growth phase, resulting in greater grain sink strength under stressed and unstressed environments

English

MP|Crop Science Society of America (CSSA)|R95ANALY|1

Lucia Segura

CIMMYT Staff Publications Collection