The term ‘heterosis’ (or hybrid vigour) characterizes the increased ability or a hybrid as compared to the parental forms. The term ability means the favourable changes in hybrid characters when compared to the abilities of P (Parental) in one or several characters. The term heterosis was first coined by Shull in 1914. Generally heterosis manifested as an increase in vigour, size, growth, yield or some other characteristics. But in some cases, hybrid ...
