Maize Pollen Viability and Ear Receptivity under Water and High Temperature Stress1
- J. B. Schoper,
- R. J. Lambert and
- B. L. Vasilas2
Pollen viability and ear receptivity may be important determinants of maize (Zea mays L.) seed set under drought and high temperature conditions. Little quantitative information is available concerning the influence of water and heat stress on pollen viability, as determined with seed-set-limiting pollen amounts, or ear receptivity. The purpose of this investigation was to determine the effect of a water deficit on ear receptivity, of heat and water stress on pollen viability using a seed-set-limiting amount of pollen in pollination, and the genotypic variability for these effects. During a 2-y period, field-grown potted maize plants, grown in a soil mix containing a Typic Argiudoll, were well-watered or water-stressed during flowering. Tassels included heat-stressed, water-stressed, and well-watered. A second experiment, conducted on a Typic Haplaquoll, involved mixing heat-stressed and nonstressed pollen with field-produced R-nj pollen and using kernel ratios to determine viability. The heat-sensitive, commercial, and prolific hybrids decreased in kernel number by 31,15, and 9% respectively when the female plants were water stressed. Kernel number did not decrease when pollen from a water-stressed plant was used. Heat stressing the tassel resulted in kernel number decreases of 87, 53, and 72% for the heat-sensitive, commercial, and prolific hybrids, respectively. Pollen viability and amount shed limited seed set when the heat-sensitive and prolific hybrids' tassels were heat stressed. Pollen viability limited seed set when the commercial hybrid's tassel was heat stressed. The pollen mixing experiment also indicated a large effect of heat stress on pollen viability. Thus, water and heat stress had large effects on ear receptivity and pollen viability, respectively, but pollen viability was unaffected by a water deficit.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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