Shattering tolerance in Brassica napus L.

Abstract

Brassica is the second-largest oilseed crop after Soybean. The total production of Brassica in the overall world is 71 million tons. In Pakistan, its total production per unit area is very low. Biotic and abiotic stresses mainly affect the brassica crop. In agriculture, shattering is the dispersal of crops seeds before their ripening. The pod wall shatters and breaks apart when it loses its hydration and cells split in a dehiscence zone organized at a suture between the edge of the lignified pod and the vascular tissue replum. The degeneration of middle lamella and loss of cellular cohesion in the dehiscence zone are the main reasons for pod shattering and seed losses. Grain yield losses in Brassica vary from 10 to 25 percent due to shattering. More than 400 kg has-1 or 12% seed losses can be occurred due to pod shattering under unfavorable conditions. Insect pest and disease damage also accelerate ripening and pod shattering. The main breeding techniques for developing rapeseed grain yield potential are a good knowledge and application of the morphological, physiological, and genetic basis of grain yield. Modern technologies, such as embryo rescue, marker-assisted breeding, and novel variation (mutation), may make it much simpler to introduce new rapeseed types having shattering tolerance than traditional methods. Thus, an overview of anatomical and physiological aspects and genetics of shattering is presented in the context of recent advances in molecular genetics and several agronomic managements to avoid shattering in Brassica.