VARIATION IN ABSORPTION OF PHOTOSYNTHETIC ACTIVE RADIATION (PAR) AND PAR USE EFFICIENCY OF WHEAT AND MUSTARD GROWN UNDER INTERCROPPING SYSTEM

Abstract

Absorption of PAR (Photosynthetic active radiation) by wheat and mustard crop and PAR use efficiency were
estimated from a two year experiment of wheat-mustard intercropping system. The experiment comprised of five
treatments (T1-sole wheat, T2- sole mustard, T3 -two wheat: six mustard, T4: four wheat: four mustard, T5: six
wheat: two mustard) allotted to RBD with 6 replications in a plot of 54m2. The sole wheat absorbed nearly 80%
of the incident PAR at 11.30h throughout growth phases. Among the intercrop treatments, T4 recorded very high
absorption. In mustard, T3 absorbed approximately 80% of the incident PAR. Mean RUE (Radiation use effi-
ciency) for dry matter production in wheat ranged from 1.84-2.99 g MJ-1 for different treatment combinations and
in mustard, it ranged from 2.33-4.34 g MJ-1. The RUE for grain yield ranged from 1.07 to 2.88 g MJ-1 and 0.43 to
1.23g MJ-1 for wheat and mustard respectively. Sole crop recorded higher RUE than the component crops under
intercropping.