Mungbean grown as intercrop suffers shading stress form companion crop at different growth stages. Grain filling stage, which appears to be very much sensitive to light conditions, needs special attention to deal with, in order to maximize the benefit from intercropping systems. Growth and yield response of mungbean to different shading conditions imposed at the onset of pod formation stage was evaluated. Shading nets were used to cut down the incident photosynthetic active rediation by 15 %, 45 % and 75 %. There was almost no difference between the control and 15 % shaded plants for all the parameters studied. Total dry weight was found to decrease with increase in shading intensity and this phenomenon continued till the maturity of the crop. The crop growth rate, relative growth rate and net assimilation rate decreased due to shading. Lower specific leaf weight and higher chlorophyll content were due to increased shading. Decreased photosynthetic active radiation caused significant reduction in pods per plant and thus there was a significant decrease in seed yield per plant. In order to avoid yield loss due to shading at grain filling stage, agronomic manipulation and selection of suitable genotypes are necessary.

Shifting cultivation, popularly known as jhum, is a dominant form of agriculture in the Chattogram Hill Tracts (CHT) of Bangladesh with upland rice being the major component of the system. The region is known for its rice biodiversity, which is under threat. This study was an attempt to explore the extent of rice biodiversity and variation in rice yields observing 81 randomly selected shifting cultivation plots from 26 dispersedly located mountainous villages in four sub-districts of Bandarban, one of three districts of the CHT. A total of 28 landraces of upland rice was grown in shifting cultivation. Highest number of landraces (16) was found in sub-district Thanchi. Three landraces most frequently observed were Gunda, Maemonsing and Sadabinni. Rice grain yield varied between 1.421 t ha-1 and 3.442 t ha-1 across landraces with the highest being recorded for Patobi. Landrace Dilon the lowest yield. Relative performance of landraces Kobrokbinni, Maemonsing, Monthon, Patobi and PD were superior to standard BRRI dhan83 and Gunda in relation to grain yield. Some of these landraces having wider adaptability may be released as varieties.