Molecular Approaches for the Improvement of Under-Researched Tropical Fruit Trees: Jackfruit, Guava, and Custard Apple

Fruit trees are important as additional sources of revenue and are important diet supplements. Besides yielding edible fruits, there are several other useful products available from these fruit trees. However, despite their significance, these plants have not been researched thoroughly for their propagation, cultivation and molecular characterization. Unlike the annual agricultural crops, fruit trees present certain unique problems in terms of their improvement. The long pre-bearing age and highly heterozygous cross pollination nature of these crops constitute a serious problem for their rapid improvement and assessment of available variability. With changing socio-economic and environmental values, there is now a worldwide burgeoning of interest and support for research on the maintenance, genetic improvement and efficient use of fruit tree resources and their products. However, some of the useful fruit trees have not been investigated in detail. In this review, biotechnological intervention in the area of tissue culture, molecular markers and genetic transformation on three under-researched tropical fruit tree crops viz. Jackfruit, Guava, and Custard apple are described.