Temperature effects on in vitro pollen germination and pollen tube growth of soybean genotypes.
(S-salem750594-poster)
Authors:
M.A. Salem* - Mississippi State University V.G. Kakani - Mississippi State University K.R. Reddy - Mississippi State University
Abstract:
Recent global climate model projections suggest that the global mean surface air temperatures will increase by 1.4 to 5.8°C by 2100 AD resulting in reduced crop yields. Soybean is one of the major crops grown in the US with 32% of total world acreage and high temperatures occurring during flowering period reduce pod set and yield. The objectives of this study were to study the effects of temperature on soybean pollen germination and pollen tube growth and to understand the genotypic variation in response to temperature. Growing each genotype in large pots under ambient conditions tested a total of 45 genotypes. Pollen collected from flowers that opened between 0900 and 1000 h was subjected in vitro to temperature treatments that varied from 15 to 50°C with 5°C intervals. Genotypic variability was observed for pollen germination percentage, pollen tube length and the cardinal temperatures calculated for these two processes. Maximum pollen germination was between 70 to 91% and for pollen tube length was between 351 to 515 µm. The mean cardinal temperatures (Tmin T opt and Tmax ) averaged over 45 genotypes were 13.3, 30.3 and 47.2 °C for pollen germination and 11.2, 35.9 and 47.6°C for pollen tube
growth. Curve fitting analysis showed that a modified bilinear model best describe the response to temperature of percentage of pollen germination and a quadratic model was the best for maximum pollen tube growth. The genotypes were grouped into sensitive and tolerant based on pollen parameters. The identified high
temperature tolerant genotypes might be useful in the future breeding programs.
Speaker Information: Mohammed Salem, Mississippi State University, Department of Plant and Soil Science, Box 9555, Mi, starkville, MS 39762; Phone: 662-325-9459;
E-mail: [email protected]