I. Bally

Changes in the cuticular surface during the development of mango (Mangifera indica L.) cv. Kensington Pride

The surface morphology of mango fruit, cv. Kensington Pride, was studied throughout fruit development to gain an understanding of the development of the cuticular structures. This was done to identify possible weaker points where water and chemicals may penetrate and lead to skin disorders. At anthesis, no epicuticular wax fine structure was evident on the flower ovary and the surface of the cutin layers was smooth and unbroken. By fruit set, a thick layer of flattened polygonal epicuticular wax scales was evident on the surface. When the fruit diameter reached approximately 3 mm the epicuticular wax scales had developed a series of slightly flattened radiating wax rodlets on their base and perimeter. At about 12 mm fruit diameter, the epicuticular wax scales with radiating rodlets began to fragment and the cutin layers began to crack, forming irregular cuticular platelets. At this stage, a third form of epicuticular wax was evident as small erect scales projecting from the cuticle surface, these became the dominant wax form in mature fruit. As the fruit developed, the number of cuticular platelets increased by subdivision and became a more regular pentagonal shape. The thinnest points of the cuticle were in the central cracks of the cuticular platelets. These cracks may be possible entry points for chemicals, leading to skin blemishing.

Genetic map of mango: a tool for mango breeding

Mango (Mangifera indica) is an economically and nutritionally important tropical/subtropical tree fruit crop. Most of the current commercial cultivars are selections rather than the products of breeding programs. To improve the efficiency of mango breeding, molecular markers have been used to create a consensus genetic map that identifies all 20 linkage groups in seven mapping populations. Polyembryony is an important mango trait, used for clonal propagation of cultivars and rootstocks. In polyembryonic mango cultivars, in addition to a zygotic embryo, several apomictic embryos develop from maternal tissue surrounding the fertilized egg cell. This trait has been associated with linkage group 8 in our consensus genetic map and has been validated in two of the seven mapping populations. In addition, we have observed a significant association between trait and single nucleotide polymorphism (SNP) markers for the vegetative trait of branch habit and the fruit traits of bloom, ground skin color, blush intensity, beak shape, and pulp color.

Mango (Mangifera indica L.) Breeding

Mango Mangifera indica L. in the family Anacardiaceae is a large evergreen tree that grows throughout the tropical and subtropical regions of the world and bears a popular tropical fruit that is consumed locally and traded globally. Preferred mango varieties vary from country to country, with subcontinental Asian varieties typically being monoembryonic and South East Asian varieties being polyembryonic. The genus Mangifera consists of many species with M. indica being the most abundant, however several of the other species are graft and pollination compatible with M. indica and are useful as rootstocks or sources of novel genes for breeders. Mango presents several challenges for breeders; it is a recalcitrant species with seed viability declining rapidly, weeks, after fruit maturity, Polyembryonic varieties can only be used as pollen parents and one seed per fruit limits the number of progeny that can easily be generated per family. Incompatibility within and between species makes hand pollination success rates lower than many other species. Knowledge of the genes and gene markers associated with important traits is in its infancy, however there is considerable effort internationally to improve the knowledge of mango genetics. This chapter on mango breeding includes many recent advances in the biotechnological aspects of mango breeding that have occurred over the past decade. The chapter looks at the tools required to carry out a modern mango breeding program reviewing genetic resources, breeding program goals, stages and design and molecular breeding tools such as marker assisted selection, saturated linkage maps and transcriptome sequencing.