Genetic diversity of Kensington mango in Australia

The genetic diversity of Kensington mangoes (Mangifera indica L.) was investigated using random amplified polymorphic DNA (RAPD) analysis. DNA was extracted from leaves of 27 'Kensington Pride', 2 'R2E2' and 1 seedling. RAPD analysis with 10 oligonucleotide primers allowed the scoring of 107 markers. The R2E2 trees (20% dissimilarity) and the seedling (10% dissimilarity) were distinct from the Kensington Pride. However, there was very little evidence of significant genetic variation within Kensington Pride selections. Fifteen of the selections were identical in all 107 markers. Only 2 selections, WEAN2 and ML2N1, differed by more than 5%. These plants provide the best options for use in genetic improvement of the Kensington Pride mango. Many of the differences found in Kensington mango orchards may be due to environmental factors not genetic variations

Prediction of breeding values for average fruit weight in mango using a multivariate individual mixed model

Mango is an important horticultural fruit crop and breeding is a key strategy to improve ongoing sustainability. Knowledge of breeding values of potential parents is important for maximising progress from breeding. This study successfully employed a mixed linear model methods incorporating a pedigree to predict breeding values for average fruit weight from highly unbalanced data for genotypes planted over three field trials and assessed over several harvest seasons. Average fruit weight was found to be under strong additive genetic control. There was high correlation between hybrids propagated as seedlings and hybrids propagated as scions grafted onto rootstocks. Estimates of additive genetic correlation among trials ranged from 0. 69 to 0. 88 with correlations among harvest seasons within trials greater than 0. 96. These results suggest that progress from selection for broad adaptation can be achieved, particularly as no repeatable environmental factor that could be used to predict G × E could be identified. Predicted breeding values for 35 known cultivars are presented for use in ongoing breeding programs

Response of Endogenous Hormone Concentrations to Two Floral Inductive Treatments, viz. KNO3 and PBZ, in Mango cv. ‘Tommy Atkins’ Growing Under Tropical Conditions

Floral induction (FI) has been intensively studied in mango, more under sub-tropical than under tropical environments. Decreases in temperature below 20 °C, which is common in sub-tropical regions but seldom occurs in many tropical ones, has been considered a critical factor for FI in this species. Trying to understand the way by which two FI treatments, potassium nitrate (KNO3) and paclobutrazol (PBZ), can regulate flowering by modulating the endogenous concentrations of plant hormones, the following compounds were analyzed in terminal buds, wood and bark sections of lateral branches from treated and untreated ‘Tommy Atkins’ mango trees growing under tropical conditions: indole-acetic acid (IAA), gibberellins (GAs), zeatin/zeatin riboside (Z/ZR) and N 6 (Δ2-isopentenyl) adenine/N 6 (Δ2-isopentenyl) adenosine. Behavior in the contents of these endogenous hormones was often irregular but their course was in general similar for all three treatments. However, levels of GAs were consistently lower in most evaluations of wood and bark sections of PBZ-treated trees compared to KNO3-treated and control plants. In contrast, the endogenous levels of the presumably FI promoting Z/ZR raised considerably at the time close to FI in buds of KNO3-treated trees. These KNO3-treated trees flowered earlier and more profusely than those from other treatments. Although PBZ could be related in this work to a reduction in GA contents, no direct influence of this compound over FI could be established. KNO3 might partially exert its promoting effect on mango FI by increasing Z/ZR contents.Universidad de Costa Rica/[734-A5-180]/UCR/Costa RicaGerman Academic Exchange Service/[]/DAAD/AlemaniaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro para Investigaciones en Granos y Semillas (CIGRAS