No abstract

No abstract

Suitability of sweet sorghum in Greece, where irrigation supply during crop development is limited as rainfall is scarce and evapotranspiration loss is high, is examined in relation with radiation availability. A two-year field experiment was conducted, in central Greece, imposing four soil water regimes via different irrigation treatments: (1) Highly irrigated, (2) Highly irrigated till anthesis when irrigation stopped, (3) Medium irrigated, and (4) Low irrigated. It was found that above-ground dry biomass production from nonwater-stressed sweet sorghum plants suggests a high productivity potential among C 4 crops. Under water shortage, radiation use efficiency may be significantly lower. Radiation use efficiency seems to be linearly related to water consumption. Stressed plants (probably except severely stressed) seem to use available water more efficiently than unstressed plants. The slope of the line relating dry matter produced and water evapotranspired increases the sooner the stress is sensed. Yield reduction resulting from post-anthesis irrigation stopage is very little. High water use efficiency values tend to be related with low radiation use efficiency values.

Temperature effects on cotton yield and fibre properties of three cotton cultivars were determined. Plants were grown in pots maintained in growth rooms at varying day and night temperatures representing seasonally constant or varying (C) or daily varying (V) regimes.Yield and fibre characters responded to variation of daily mean and amplitude of temperature. Mean temperature reduction improved yield components, but fibre length, uniformity, strength and micronaire were increased by high, particularly high day, temperatures. A large daily temperature amplitude produced an intermediate number of flowers and the lowest retention percentage.Fruiting and yield were increased by reduction in temperature down to the threshold mean temperature of 22°C. However, V-regimes with a low minimum temperature acted as a further drop (below 22°C) of temperature and adversely affected these characters. An adverse effect of low minimum temperature combined with a moderate day temperature was observed also on lint percentage and fibre properties.Varietal differences were more pronounced for highly heritable characters such as fibre properties, for which significant interactions between varieties and temperature also occurred. Differences in reproductive development were not sufficient to be of much practical importance.

No abstract