Genetic diversity in Aloe and its breeding strategies

Aloe vera gained its commercial importance in medical and cosmetics industry recently. Currently it is being collected from the wild sources posing a serious problem of depletion of its resources in its natural stands. Therefore it is important to bring A vera into the mainstream of cultivation by developing improved varieties and its agronomic practices as there is no improved or notified varieties across the country for its commercial cultivation. As genetic divergence is the pre-requisite for any crop improvement programme, an attempt has been made to review the genetic diversity reported by various workers to arrive at an assessment of genetic diversity available in Aloe both at inter- and intra-specific levels. The review revealed that there is a quantifiable huge genetic diversity exiting in Aloe for its growth, yield and quality parameters. The practical utility of using molecular marker analysis like RAPD, AFLP and ISSR to estimate the genetic diversity at molecular level has also been reviewed. The primers having high polymorphism information content value for diversity studies and primer with the highest discrimination index used for identification of different accessions were also suggested. The intra-and inter-cluster distances worked out by D² statistics and cluster analysis also revealed the existence of substantial diversity among the accessions and hence there is a wide scope to initiate necessary programmes to evolve high yielding varieties and/or hybrids adopting methods such as clonal selection, hybridization, mutation breeding etc.