Phenology and productivity of mustard (Brassica juncea L.) under varying sowing environment and irrigation levels

Abstract

A field experiment was conducted at Rajasthan College of Agriculture, Udaipur (Rajasthan) during
rabi seasons of 2008-09 and 2009-10 to study the effect of thermal regimes on phenology and
productivity of mustard (Brassica juncea) variety Bio-902. The experiment consisted of four dates of
sowing (5th October, 20th October, 4th November and 19th November) and four irrigation levels (no
irrigation, at vegetative stage, at vegetative and flowering stages and at vegetative, flowering and
siliquae development stages). The experiment was laid out in split plot design having four
replications. Regression models were developed to predict the seed yield of mustard. The crop
sown on 5th October and 20th October gave the maximum seed yield (17.01q ha–1) and significantly
higher harvest index over 4th November and 19th November sown crops. Seed yield of mustard have
positive correlation with maximum and minimum temperatures up to 75 DAS, thereafter, negative
correlation was observed from 90 DAS to maturity. An increase of 1.0°C mean temperature during
90 to 105 DAS caused reduction in seed yield by 4.0 q ha–1. The mean temperatures of 21.0 to 25.5°C
and 18.7 to 20.5°C during vegetative and reproductive phase, respectively, was found conducive
for higher productivity in mustard. Number of days for reproductive phase, growing degree days
(GDD) and helio thermal unit (HTU) decreased with the successive delay in sowing. Late sown
crop exhibited higher canopy temperature at 75 and 90 DAS. Application of three irrigations gave
significantly higher seed yield by 92.0, 28.0 and 4.0 per cent over no irrigation, one and two irrigations,
respectively.