Adverse high temperature effects on pollen viability, seed-set, seed yield and harvest index of grain-sorghum [Sorghum bicolor (L.) Moench] are more severe at elevated carbon dioxide due to higher tissue temperatures

Sorghum plants were exposed at head emergence to simulated heat waves for five days, and subsequent grain production observed. Comparisons were made between relatively dry heat (108�F, 41 per cent RH by day and 90�F, 53 per cent RH by night), more humid hot conditions (107�F, 70 per cent RH-90�F, 70 per cent RH), and ambient (81�F, 64 per cent RH-71�F, 85 per cent RH). Whole inflorescences or portions that had emerged before heat application were little affected, whereas most enclosed flowers were killed. High temperature was responsible, humidity having little effect. Grain yield depended on the resulting number of grains. There was some loss of pollen viability in the dry heat treatments, but not sufficient to affect seed set.

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Effects of season-long high temperature growth conditions on sugar-to-starch metabolism in developing microspores of grain sorghum (Sorghum bicolor L. Moench)

Planta ◽

10.1007/s00425-007-0595-y ◽

2007 ◽

Vol 227 (1) ◽

pp. 67-79 ◽

Cited By ~ 91

Author(s):

Mukesh Jain ◽

P. V. Vara Prasad ◽

Kenneth J. Boote ◽

Allen L. Hartwell ◽

Prem S. Chourey

Keyword(s):

High Temperature ◽

Sorghum Bicolor ◽

Growth Conditions ◽

Grain Sorghum ◽

Starch Metabolism ◽

Temperature Growth ◽

Sorghum Bicolor L

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Accumulation of free proline in sorghum (Sorghum bicolor) pollen

Canadian Journal of Botany ◽

10.1139/b96-006 ◽

1996 ◽

Vol 74 (1) ◽

pp. 40-45 ◽

Cited By ~ 19

Author(s):

A. R. Lansac ◽

C. Y. Sullivan ◽

B. E. Johnson

Keyword(s):

Low Temperature ◽

Grain Yield ◽

Sorghum Bicolor ◽

Low Temperatures ◽

Seed Set ◽

Grain Sorghum ◽

Free Proline ◽

Seed Number ◽

Proline Concentration ◽

Sorghum Bicolor L

Suboptimal temperatures cause grain yield reductions generally associated with low seed-set in sorghum [Sorghum bicolor (L.) Moench]. Low proline concentration in pollen has been associated with cold-induced male sterility. This study was done to (i) determine free proline concentrations in grain sorghum pollen after low temperature exposure, (ii) determine the relationship between seed-set and proline concentration in pollen, and (iii) determine the association of proline concentration in pollen with grain yield in sorghums of different maturity. Eleven sorghum genotypes, grown in a greenhouse at 27/22 °C (day/night) until the early boot stage were transferred to 20/10 °C in growth chamber until physiological maturity. Concentration of proline in pollen was determined at anthesis and related to seed number and grain yield. Proline concentrations in pollen increased from 19 to 36 μg∙mg−1 fresh wt. to 30 to 49 μg∙mg−1 fresh wt. at low temperatures. Seed number and grain yield were reduced by low temperature in most of the genotypes. Percent seed-set in male sterile lines was significantly correlated (r = 0.45**) with free proline concentrations in the pollen from 13 fertile hybrids grown under cold or control conditions. Higher concentrations of proline in pollen under cool and also control temperatures seemingly contribute to greater pollen viability in grain sorghum. In 21 sorghum hybrids grown under control temperatures, seed number per panicle was found correlated (r = 0.42*) to free proline concentrations in pollen. Genotypic differences in pollen proline concentration were not associated with differences between maturity groups. Keywords: Sorghum bicolor (L.) Moench, pollen, free proline, low temperatures, seed-set, grain yield.

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