ISSN:
1435-0653
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Sorghum bicolor (L.) Moench]. Nine genotypes were grown in pots at mean temperatures of 17 to 33°C and photoperiods of 11.0 to 12.3 h d-1 in glasshouses. Leaf-tip appearance was recorded every 3 to 5 d and PI determined by apical dissection. The optimum temperature (To) for 1/PI was between 26 and 27°C and supra-optimal temperatures delayed PI in all genotypes. The base temperature (Tb) ranged from 6 to 10°C but only one genotype had a Tb significantly different from a common value of 8.5°C. Growing degree days (GDD) for PI among genotypes at sub-optimal temperatures varied from 411 to 592 (P 〈 0.001) above a Tb of 8.5°C. Warmer temperatures (〉 27°C) reduced the rate of leaf-tip appearance in five genotypes; in the remaining genotypes the rate of leaf appearance was effectively constant at mean temperatures between 23 and 33°C. There was no significant difference (P 〉 0.20) among genotypes in the phyllochron, which was 57 GDD above a Tb of 8.5°C. The final number of leaf-tips was constant within genotypes at mean temperatures of 18 to 30°C, but varied among genotypes from 11.8 to 17.3. In conclusion, the Tb and To for 1/PI were approximately 8.5 and 27°C and there was variation in 1/PI but not in the rate of leaf-tip appearance among the genotypes studied.
Type of Medium:
Electronic Resource
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