Recent advances in genetics and molecular breeding of parthenocarpic cucumber (Cucumis sativus L.) under protected conditions

Cucumber is an important member of Cucurbitaceae family which is grown and consumed globally. It is consumed in the form of salads or pickles and has abundant supply of minerals and vitamins. It has been a focus of extensive research due to its publically available genome sequences. Marker assisted breeding has been employed to generate improved varieties of cucumber with resistance to various diseases besides desirable horticultural traits. One such trait is the production of parthenocarpic fruits i.e. seedless fruits developed in the absence of pollination. Naturally, parthenocarpy occurs under unfavourable environmental conditions. However, it is possible to artificially induce parthenocarpy by applying plant growth regulators. At molecular level, parthenocarpy is a result of complex role-play of genes and hormones with tight regulation. Many researchers aim at developing parthenocarpic varieties by either transferring the trait into existing varieties with resistance to specific diseases or by knocking off genes controlling parthenocarpy. A comprehensive knowledge of background and genetics of parthenocarpy is required in both cases. This review includes an-inclusive study of the molecular basis of parthenocarpy. The genes and hormones involved and their functions, inheritance of parthenocarpy and markers associated with it have been given in detail.