Vol. 12, Issue 12 (2023)

Author(s):
SV Patel, NM Gohel and AD Kalola

Abstract:
Cotton (Gossypium herbaceum L.) is a globally important crop used for both its natural fiber and seed. In Gujarat, desi cotton-growing areas are divided in to four well-defined zones among that the desi cotton grown specifically in Wagad cotton zone. Among the diseases of cotton, root rot caused by M. phaseolina (Tassi) Goid. is widely distributed and causing up to 90 per cent or more disease incidence infield resulting in heavy yield losses. The maximum temperature, bright sunshine hours and evaporation positively correlated with the root rot disease incidence and found to have a key role in increasing the disease incidence whereas minimum temperature, rainfall, wind speed, morning relative humidity and evening relative humidity negatively correlated with the disease incidence. The effect might be due to moisture stress condition and higher temperature coincide with the progress of disease. The significant interaction effect of year, date of sowing and varieties/ genotypes of desi cotton revealed that lowest disease incidence was recorded susceptible variety/ genotype sowing at 4^th week of July. The AUDPC was found utmost in moderately resistant variety/ genotype (V2) (5840.46) sowing on 4^th week of June (D1) with the rate of infection (r) 0.02 followed by susceptible variety/ genotype (V3) recorded 5131.71 and 4582.92 AUDPC with 0.03 infection rate sowing on 2^nd week of July and 4^th week of June, respectively.