CROP IMPROVEMENT STUDIES WITH FLOWER ENHANCING AND FRUIT SET IMPROVING CHEMICALS IN MANGO (Mangifera indica L.) cv. BANGANPALLI

An experiment on the effect of flower enhancing chemicals (Ca (NO3)2 (1%), KH2PO4 (1%) and H3PO4 (0.5%)) and fruit set improving chemicals (Spermidine @0.01mM, spermine @0.1mM and boron-20% @ 1.25gm.l-1) on percent flowering, fruit set and yield of mango. KH2PO4 and H3PO4 alone or in combinations with fruit set improving chemical significantly increase in percent of flowering, panicle length and breadth when compare to control trees. Significantly the highest fruits.panicle-1, yield and fruit.tree-1 (16.7 % over control) and was recorded in Ca (NO3) 2 applied trees and spermidine (22.9% over control) applied trees alone compare to control. Spermidine alone could able to significantly increase the fruit.panicle-1 and final retention of fruits and increased the fruit weight reflecting in the overall increase in yield by 48.72 %. Among the combination, maximum increase in yield over control was recorded in Ca (NO3)2 + spermidine (87.27 %), H3PO4 + spermine (76.09 %), KH2PO4 + Spermine (74.51 %). However, based on benefit cost ratio spraying of Ca (NO3)2 + spermidine has give maximum benefit cost ratio of 3.35. KEY WORD: Flower enhancing chemicals, Fruit set improving chemical, per cent flowering, Polyamines, Mango. INTRODUCTION Mango (Mangifera indica L.) is a major fruit crop of the tropical regions of the world. India is the largest producer of mango in the world. The fruits of mango are valued because of its excellent flavor, delicious taste, and nutritive value. Andhra Pradesh ranks first in the production of mango. In Andhra Pradesh, mango occupies an area of 4.89 lakh ha, with a production of 44,406.9 M.T. with a productivity of 9.0 T. ha ̅1 (NHB Database, 2012). Of late, the production and productivity of mango cv. Banganpalli has been decreased in the past 4-5 years (Bhagwan et al., 2011). There are several reasons for poor productivity in mango cv. Banganpalli in Andhra Pradesh. Among them, poor and erratic flowering coupled with poor or nil fruit set in mango cv. Banganpalli is one of the major reasons for poor productivity. To mitigate these production problems there is much need to use the flower promoting and fruit set improving chemicals. Various chemicals application has been standardized for enhancing and uniform flowering in mango. Spraying of various chemicals like Ca (NO3)2 (Kumar raj et al., 2005), KH2PO4 (1%) (Bhagwan et al., 2011)), H3PO4 (Kumar raj et al., 2007) has been standardized to enhance the flowering in mango cv. Banganpalli. For improving the fruit set, spraying of polyamines like spermidine @ 0.01mM and spermine @ 0.1mM at full Bloom stage were standardized in mango cv. Kensington pride (Aman ullah Malik and Zora singh 2006). Among the micronutrients spraying of boron at full bloom stage has significantly improved fruit set in mango (Saleh and El-Monem 2003). MATERIALS & METHODS The experiment was conducted on fifteen years old, well grown, uniform statured trees of mango cv. Banganpali. Trees were spaced with 8 m and planted in square system. The statistical design adopted was Factorial Randomised block design with 12 treatments which were replicated thrice. To prepare 1% of ca (NO3)2 one gm of Ca (NO3) 2 was dissolved in 1 litre of water. One gm of Potassium di hydrogen orthophosphoric acid (KH2PO4) was dissolved in 1 litre of water to get 1% of KH2PO4. One ml of phosphoric acid (H3PO4) was dissolved in 2 litres of water to get 0.5% of H3PO4. Ca (NO3)2, KH2PO4 and H3PO4 @ 0.5% were sprayed at the time of panicle initiation was found to improve flowering in mango cv. Banganpalli (Kumar raj et al., 2005). 1.45 mg of spermidine was dissolved in 1 litre of water to get 0.01 mM of spermidine. 20mg of spermine was dissolved in 1 litre of water to get 0.1 mM of spermine. 1.25 gm of boron (20%) was dissolved in 1 litre of water to get 1.25 g.l-1 of boron. Fruit set improving chemicals (spermidine, spermine and boron) were sprayed at full bloom stage (Sanna et al., 2005). Data on percent flowering, panicle length and breadth, fruit set per panicle, fruits per tree and yield were recorded. Fifty shoots were randomly tagged (from North, South, East and West directions) and the number of tagged shoots which had flowered was recorded and expressed as percentage of flowering. The panicle length, breath and fruit set of ten randomly selected shoots were recorded and mean was calculated. The total number of fruits harvested per tree was counted after harvest and expressed as number of fruits per tree. The average fruit weight was Crop improvement studies in mango 147 computed by dividing the total yield (kg per tree) and number of fruits per tree of the respective treatment. RESULTS & DISCUSSION Flowering parameters Changes in percent flowering (%) of mango cv. Banganpalli sprayed with different flower enhancing chemicals and fruit set improving chemicals are presented in the Table 1. At initial stage of flowering (Dec 20th) There was significant difference in percent flowering (%) among different flower enhancing chemicals application. Maximum percent flowering was recorded in application of Ca (NO3)2 (C1) (7.42), which were on par with application of KH2PO4 (C3) (5.92). Minimum percent flowering was recorded in untreated (C0) (3.23), which were on par with application of H3PO4 (C2) (5.11). At 20 days after initial stage of percent flowering (Jan 10th) maximum percent flowering was recorded in application of KH2PO4 (C3) (39.51), which were on par with application of H3PO4 (C2) (34.75) and Ca (NO3)2 (C1) (32.85). Minimum percent flowering was recorded in untreated control (C0) (22.85). At 40 days after initial stage of percent flowering (Feb 1st) maximum percent flowering was recorded in application of KH2PO4 (C3) (68.01), which were on par with application of H3PO4 (C2) (60.94) and Ca (NO3)2 (C1) (59.87). TABLE 1: Effect of flower enhancing and fruit set improving chemicals on per cent flowering (%) of mango cv. Banganpalli. Figures with same alphabets did not differ significantly. ** Significant at (p= 0.01 LOS), *Significant at (p= 0.05 LOS), NSNon Significant. Values were compared with respective C.D values. F1 Spermidine 0.01mM C1 Ca(NO3) 2 @ 1% F2 Spermine 0.1mM C2 H3PO4 @ 0.5% F3 Boron 1.25g.l-1 C3 KH2PO4 @ 1% F0 – Control C0 Control TABLE 2: Effect of flower enhancing and fruit set improving chemicals on panicle length (cm) of mango cv. Banganpalli Treatment Panicle length (cm) C1 Ca(NO3) 2 1% C2 H3PO4 C3 KH2PO4 C0 Control Mean F1 Spermidine 0.01mM 16.10b 15.86b 15.76b 12.73a 15.11 F2 Spermine 0.1mM 14.66b 12.20a 18.56c 15.33b 15.18 F3 Boron 1.25g.l-1 15.93b 13.46a 17.06c 13.26a 14.92 F0 Control 16.83b 13.66a 15.96b 13.66a 15.02 Mean 15.88b 13.79a 16.83b 13.74a F Test S.Em ± CD at (5%) Factor F * 0.403 NS Factor C * 0.403 1.164