A Review of Factors Affecting Pod Shattering in Soybean (Glycine max)

Soybean is an important crop in the world cultivated for its oil and protein content. It is a significant component of the small holder cropping system and has the potential to become a major crop produced in Africa. However, its productivity is hampered by a number of biotic and abiotic factors. Among the important biotic factors affecting the yield of soybean is pod shattering. Pod shattering is the opening of mature pods along the dorsal or ventral sutures (located along the length of the pod) when the crop matures or during harvesting resulting in seed dispersal. It is a quantitative trait that is influenced by one major gene and a few minor genes and is also highly heritable. It can cause yield losses of up to100%. Apart from causing yield losses, pod shattering may pose a challenge to the crop rotations in the following seasons as seeds from shattered pods tend to emerge as volunteer weeds. There are a number of factors that are linked to pod shattering. An overview of the morphological, anatomical, environmental and genetic aspects associated with pod shattering in soybean is discussed in this review. Understanding all the factors underlying pod shattering in depth is key in breeding soybean varieties that delay to shatter. This can help breeders in knowing which approach to take in breeding for soybeans with pods that delay to shatter. Breeding strategies can focus on manipulating morphological, biochemical and anatomical traits.