Y. T. N. Reddy

Studies on the relationship between leaf number and area and fruit development in mango (Mangifera indica L.)

SummaryThe optimum leaf number: fruit ratio in various mango cuitivars was sought by isolating individual fruits with known numbers of supporting leaves by shoot girdling. 14CO2 feeding experiments showed a higher rate of carbon fixation in the leaves of girdled shoots than of control shoots but the translocation of 14C assimilates to the developing fruits on the girdled and control shoots was comparable. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable to that of leaves on control shoots. In all the cuitivars studied it was observed that 30 leaves, the maximum available on a shoot, could not support the growth of a single fruit to normal size. The results also show that fruit development depends not only on the current assimilates but also to a great extent on reserves. The utilization of reserve metabolites from vegetative organs during the ‘on’ year could be a contributing factor towards biennial and erratic bearing.

Long-term effects of rootstocks on growth and fruit yielding patterns of ‘Alphonso’ mango (Mangifera indica L.)

Abstract Results of a 21-year study on the performance of ‘Alphonso’ mango grafted on eight rootstocks established the influence of the rootstocks on the growth and fruit yielding patterns of ‘Alphonso’ scion. Nucellar seedlings of ‘Muvandan’ ‘Bappakai’ and ‘Olour’ were vigorous rootstocks in decreasing order of vigour, while those of ‘Vellaikulamban’ imparted dwarfing, in comparison with the scion grafted on its own open-pollinated zygotic seedlings. The cumulative fruit yield per tree was higher on the vigorous rootstocks, particularly ‘Muvandan’ and ‘Olour’; the latter rootstock also resulting in early higher yields of the scion. However, the fruit yields per unit canopy volume and per unit land area were higher with the dwarfing ‘Vellaikulamban’ rootstock. Based on the analysis of variance and game theory analysis of growth and yield data of several years, nucellar seedlings of ‘Vellaikulamban’ and ‘Olour’ were suggested as potential rootstocks for intensive cultivation of ‘Alphonso’ scion. Correlation studies indicated trunk cross sectional area to be a good indicator of vigour in mango and cumulative fruit yield during the initial 16 years was highly correlated with that during the subsequent years. The bienniality parameters worked out with the yield data over a number of years suggested ‘Alphonso’ to be of irregular bearing nature which was controlled more by exogenous factors than endogenous ones and slightly influenced by the rootstocks.

Growth, yield, fruit quality and leaf nutrient status of thirteen year old ‘Alphonso’ mango trees on eight rootstocks

SummaryNucellar seedlings of mango cv. Vellaikolamban were dwarfing when used as a rootstock for cv. Alphonso scions, while those of cvs Muvandan, Bappakai and Olour behaved as vigorous rootstocks, in decreasing order. There was more flowering, and less vegetative flushing when ‘Alphonso’ was grown on this dwarfing rootstock. An inverse relationship between the phenolic content of stem apical buds of the scion and tree size was observed. Differences in leaf nutrient status of ‘Alphonso’ on the various rootstocks were significant for N, K, Fe, Ca, Mn, and Cu, but not for P, Mg and Zn. Vigorous rootstocks led to higher leaf N contents and the least vigorous rootstock resulted in the lowest values of N, K, and Fe. The highest content of the last two nutrients were also recorded on the vigorous rootstocks cvs. Olour and Muvandan. Although fruit yield per tree was high on the vigorous rootstocks and low on cv. Vellaikolamban, productivity, expressed as fruit yield per unit space occupied by canopy, was higher ...

Studies on Changes in Carbohydrate Metabolism in Regular Bearing and “Off” Season Bearing Cultivars of Mango (Mangifera indica L.) During Flowering

Studies were conducted at Indian Institute of Horticultural Research, Bangalore, India, to compare the role of carbohydrate and its metabolizing enzymes in “off” season bearing cultivar Royal Special and regular bearing cultivar Totapuri during the time of flowering. Totapuri is a regular bearing cultivar mainly used for processing and has high yielding potential. “Off” seasonal cropping in mango is the unique feature of mango cultivar Royal Special which contributes to “off” season mango production under South Indian conditions. During the bud swelling stage, the maximum reducing sugars contents were recorded while higher chlorophyll a and b values were recorded during bud break stage in ‘Royal Special’ as compared to ‘Totapuri’. Higher acid invertase activity was recorded during emergence of panicles, and increased amylase activity was observed during pre-swelling stage in ‘Royal Special’. Sucrose and its metabolizing enzymatic activities increased during flowering, indicating their decisive role in the flowering process in the case of both cultivars of mango.

Harmonious Phenological Data: A Basic Need for Understanding the Impact of Climate Change on Mango

Uniformly collated phenological data set is the most important requirement for developing climate change impact models for mango. Consistently collected phenological records directly indicate the effect of change in climatic parameters by depicting shifts in phenological events. Recording of consistent data pertaining to phenophases as a function of time serves as critical input for working out integrated interaction of interannual variability, spatial differences and climate variability impacts. In general, uniform qualitative data recording is difficult in mango due to variations in plant growth and development under diverse climatic fluxes occurring in subtropical to tropical regions. Major observed effects of climate change on mango include early or delayed flowering, multiple reproductive flushes, variations in fruit maturity, abnormal fruit set and transformation of reproductive buds into vegetative ones. These critical phenophase-dependent events require supporting quantitative data representing behaviour of sufficient number of shoots within a tree for objective analysis of factors influencing them. For monitoring the phenophase dynamics, use of extended BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale developed for mango helps in monitoring the phenology by employing uniform methodology over same or different locations with the description of each phenophase in mango as distinctly classified by adopting numerical code. A manual to elucidate the methodology for general users has been developed with the help of pictorial representation of phenophases along with corresponding scores, analysis, depiction of results and interpretation for uniform data recording, and this can be downloaded from http://offseasonmango.cishlko.org/phenology.pdf.