Production Models in Brown Sarson*

Production models prepared on the basis of dry matter production and its distribution into different plant parts during various stages of growth and development provide useful information about the relative importance of different sinks as well as forage production ability of a particular genotype in a given unit of time. Further, these are also useful in determining appropriate stage for harvesting when a variety would yield maximum dry matter of good quality. The production patterns of two genotypes of brown sarson namely ‘Japan rape’ and ‘Assam Selection’ were studied. The results indicated that the production models of both these varieties were similar except for rate of production per unit of time. In both the varieties dry matter increased with the advancement of developmental stages, the rate of production being faster for ‘Japan rape’ than ‘for Assam Selection’. An important feature of dry matter distribution was the attainment of peaks by leaves and stems at different times. However, what is desired is the harvesting of crop for fodder at a stage when leaf and stem both coincided in their peak of production. This would lead to maximum dry matter production as well as good fodder quality because higher the proportion of leaves more palatable would be the fodder. The most appropriate time for harvesting corresponded with the initiation of pod information. In the present case, this period lies between 11th to 12th week after sowing for ‘Japan rape’ and 9th to 10th week for ‘Assam Selection’. Breeding for varieties, whose peaks of dry matter production by leaf and stem coincides, is suggested.