Pheno-Physiological studies on Baramasi, regular and biennial bearing mango
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Date
2015-12-17
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Department of Horticulture (Fruit & Fruit Technology), BAU, Sabour
Abstract
Flowering in mango (Mangifera indica L.) is a very complex physiological phenomenon. The potentiality to form flower buds depends on the florious condition of the tree that depends on many factors such as genotypes, climatic factors, physiological behavior, agro-techniques, pests and disease management etc. Very less information is reported on the above subject. Hence, a study was carried out at AICRP (Fruit) experimental farm of the Department of Horticulture (Fruit & Fruit Technology), Bihar Agricultural College, Sabour, Bhagalpur, Bihar during 2012-13 and 2013-14 to know the phenological behavior as well as to understand the physiological and biochemical activities during different stages. This experiment was laid out with four mango cultivars Baramasi, regular bearing (Amrapali) and biennial bearing (Langra and Alphonso) in RBD. The highest flowering intensity was produced by Langra (4295.50 flowers/sq. ft.) whereas Alphonso had longest panicle (32.86 cm), minimum flowering intensity (2621.00 flowers/sq. ft.) and panicle length in Baramasi (25.16). Results also indicated that flowering inhibit the photosynthesis (Pn) (6.22-12.11 µmol/m2/sec), stomatal conductance (gs) (0.131-0.229 µmol/m2/sec) and transpiration (E) (4.35-5.33 µmol/m2/sec) rates, these were higher during the post flowering stage however the lower values were recorded at flowering stage. The higher rate of photosynthesis was not due to variation in the water status of the leaves, since relative water content (RWC) was significantly lower in leaves of Langra. Chlorophyll has significant role in the photosynthesis. The highest chlorophyll content (2.45-4.00 mg/g) was estimated during the post flowering stage. Results also underlined the significance of chlorophyll fluorescence (Fv/Fm) system in flowering of mango. Increased accumulation of carbohydrates was also estimated during flowering stage compared to other stages in all cultivars but Baramasi exhibited almost similar level during all stages in terms of carbohydrate (88.44-89.2 8 mg/100g) as well as nitrogen content, flavonoids and total antioxidants capacity. Time of 50% flowering, panicle length, No. of flowers, No. of panicles, and hermaphrodite flowers were found to be positively correlated with Pn, gs, E, Fv/Fm while leaf area index (LAI) was positively correlated with total chlorophyll, phenolics, carbohydrates and nitrogen however, No. of flowers was correlated with carbohydrates and total chlorophyll, Pn, gs, E, Fv/Fm, total chlorophyll, temperature, RH and rainfall were positively correlated to each other whereas negatively correlated with internal CO2 concentration of leaf (Ci), relative water content (RWC), specific leaf weight (SLW), carbohydrates, phenolics and nitrogen content. Although, results are not clearly showing the actual factors involved in flowering, however this study is helpful to understand the relationship of physiology and biochemical attributes towards flowering of Baramasi, regular and irregular bearing mango. Baramasi bears five times flowers as well as more flushes in a year than other cultivars. Leaf area index observed significantly maximum in Baramasi. Higher chlorophyll content, electron transport rate, specific leaf weight and relative water content during all stages were observed in Baramasi. In the data, it was observed that Baramasi has exhibited much fluctuating carbohydrate reserve due to staggered flowering pattern during flowering process. During flowering increased level of carbohydrate reserve, indicating their decisive role in the flowering. Further works at molecular level (gene expression) are needed to understand the mango flowering. This information could be used for breeding programs to improve mango productivity by producing fruits throughout the year.