Biotechnological advances in litchi (Litchi chinensis Sonn.): present scenario and future prospects in crop improvement - a review
Crop improvement program in litchi is mainly concerned with the development of cultivars adapted to a wide range of climatic conditions, extended harvesting season and quality fruits with improved shelf life. Conventional breeding methods alone do not hold much promise in crop improvement due to the complications related to long juvenile phase, narrow genetic base, high genetic heterozygosis, lack of information about inheritance pattern of specific traits and polygenic nature of several important traits. In addition to this, in intervarietal and interspecific hybridization, the requirement of repeated backcrossing to homogenize and fix desired traits as well as additional breeding required to eliminate the unwanted traits that come along during such hybridization makes conventional breeding more cumbersome and time-consuming. Thus it becomes inevitable to evaluate the potential of biotechnological approaches for complementing and expediting the conventional breeding methods. In litchi, the use of biotechnological approaches for crop improvement is still in its infancy. However, in the past few years several studies involving in vitro regeneration, micro-propagation, genetic transformation, and marker assisted selection, etc. has been conducted at various centers around the world. Somatic embryogenesis and plant regeneration has been claimed in various genotypes of litchi. Agrobacterium tumefaciens-mediated genetic transformation is also reported. Cloning of ACC oxidase gene to enhance the storage life of fruit has been attempted. A high density molecular linkage map constructed for litchi based on AFLP and RAPD markers can provide a strong foundation for QTL location or molecular-assisted breeding. Use of molecular markers for identification and detection of cultivars and hybrids, respectively, can help in reducing the breeding cycle, hence making it more efficient. Production of synthetic seeds in litchi by encapsulating somatic embryos, shoot buds, etc. can be helpful in propagation, short-term storage and germplasm exchange and needs intensive research. In vitro conservation of embryogenic calluses has been identified as one of the methods to conserve the germplasm of litchi, thus reducing the space requirement and labor cost. The main objective of this review is to investigate the biotechnological advances made in litchi till date and their future implications in improvement of this crop.
Mir, H., Cholin, S.S. and Perveen, N. (2018). Biotechnological advances in litchi (Litchi chinensis Sonn.): present scenario and future prospects in crop improvement - a review. Acta Hortic. 1211, 123-134
litchi, biotechnology, molecular markers, crop improvement, conventional breeding, micropropagation