Effect of stripe rust (Puccinia striiformis west.) and irrigation on the yield foliage temperature of wheat

Avocet, a wheat cultivar susceptible to stripe rust (yellow rust) was grown with three levels of water input (161, 313, 542 mm) of which 161 mm was from rainfall and the rest irrigation. After the jointing stage of development, the application of fungicide sprays to one half of a set of plots was used to study the impact of stripe rust on foliage temperature and grain yield. Transpiration rates were calculated from foliage temperature and other meteorological data. During the early development of stripe rust lesions, foliage temperatures were reduced by 0.2-1.0°C compared with those of foliage protected by sprays. This effect was probably due to the rust preventing stomatal closure and rust pustules rupturing the epidermis. This caused a calculated 20-40 percent increase in transpiration rate per unit of green area index. Ten days after the appearance of rust lesions this early trent was reversed as infected areas of leaves began to die. This caused an elevation in foliage temperature of 0.6-1.6°C. The calculated reduction in transpiration associated with this elevation was less than 10 percent. In comparison, stripe rust caused a 51 percent in grain yield on the well watered plots from (4.9-2.1 t ha-1) and a 46 percent reduction on rainfed plots (2.8-1.5 t ha-1). These data confirmed that the dominant effect of stripe rust is probably on the biochemical processes of photosynthesis and assimilation. Thus the stomatally-controlled processes of H2O and C02 diffusion that are linked with changes in foliage temperature appeared to be of minor significance in causing the yield loss

Bibliographic Details

Main Authors:	119891 Smith, R.C.G., 77098 Heritage, A.D., 121480 Stapper, M., 46926 Barrs, H.D.
Format:	biblioteca
Published:	1986
Subjects:	GRANOS, TRIGO, ROYA, ENFERMEDADES FUNGOSAS, PUCCINIA STRIIFORMIS, RIEGO, RENDIMIENTO, TEMPERATURA, HOJAS, LESIONES,
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