Studies on crop regulation and fertigation in guava (psidium guajava L.) cv. sardar for growth, physiology, yield and quality

STUDIES ON CROP REGULATION AND FERTIGATION IN GUAVA (Psidium guajava L.) cv. SARDAR FOR GROWTH, PHYSIOLOGY, YIELD AND QUALITY By A. MAHADEVAN, M.Sc., (Hort.) Degree : DOCTOR OF PHILOSOPHY IN HORTICULTURE (FRUIT SCIENCE) Chairman : Dr. S.KUMAR, Ph.D., (Hort.) Dean (Horticulture) R.V. S. Padmavathy College of Horticulture Tamil Nadu Agricultural University Sempatti – 624 701 Dindigul (Dt), Tamil Nadu 2014 An experiment was conducted on “Studies on crop regulation and fertigation in guava (Psidium guajava L.) cv. Sardar growth, physiology, yield and quality” at Farmers Field, Devathana patti, Theni (Dt), Tamil Nadu during 2012 2014. The field experiment was laid out in Factorial Randomized Block Design (FRBD) replicated thrice with two factors (Factor 1Pruning, Factor 2Fertigation), i.e., different pruning levels viz., P0 Without pruning, P1 Light pruning (removal of past season growth up to 15 cm), P2 Moderate pruning (removal of past season growth up to 30 cm) and drip fertigation levels viz., F0 100 per cent recommended dose of fertilizer (RDF) as soil application and irrigation, F1 125 per cent RDF through fertigation, F2 100 per cent RDF through fertigation, F3 75 per cent RDF through fertigation, F4 50 per cent RDF through fertigation. Observations were made on biometric, physiological, flowering, yield and quality traits. The nutrients status of soil and leaf were analyzed before and after the commencement of experiment, during vegetative and harvesting stages in both the seasons. The results of the investigation revealed that the morphological, physiological, yield and quality characters were significantly influenced by different pruning levels and drip fertigation treatments. Among the different pruning levels, P2 moderate pruning (removal of past season growth up to 30 cm) increased the tree height, tree spread, fresh weight of pruned branches and number of new shoots emerged from pruned branches and shoot length resulting with earlier flowering in both the seasons. The physiological parameters viz., light transmission ratio, total chlorophyll content, carbohydrate content, C/N ratio were high in this treatment. The yield characters viz., percentage of fruit set, fruit length, number of fruits per tree, fruit yield per tree, average fruit weight, fruit volume, fruit diameter, seed and pulp ratio were high in moderately pruned (30 cm) trees. The quality characters like total soluble solids, titrable acidity, ascorbic acid content, total sugars, reducing sugars, nonreducing sugars and pectin content were higher in moderately pruned (30 cm) trees. The available soil and leaf nutrient (N, P and K) status were recorded the highest value in the same treatment. Among the different fertigation levels, drip fertigation 125 per cent RDF (F1) helped in increasing the tree height, tree spread, fresh weight of pruned branches and number of new shoots emerged from pruned branches, shoot length, early flowering in both the seasons. The physiological parameters viz., light transmission ratio, total chlorophyll content, carbohydrate content and C/N ratio were higher in this treatment. Similarly, application of 125 per cent RDF through drip fertigation recorded the highest yield characters viz., percentage of fruit set, fruit length, number of fruits per tree, fruit yield per tree, average fruit weight, fruit volume, fruit diameter and seed and pulp ratio along with the quality characters viz., total soluble solids, titrable acidity, ascorbic acid content, total sugars, reducing sugars, nonreducing sugars and pectin content. Analysis of the soil and leaf nutrients status at the different stages of crop growth indicated that application of 125 per cent RDF through drip fertigation recorded the highest level of available soil and leaf nutrient (N, P and K) contents. The treatment combinations of (P2F1) moderate pruning (30 cm) with drip fertigation of 125 per cent RDF had significantly registered the higher plant height, tree spread, fresh weight of pruned branches, number of new shoots emerged from pruned branches, shoot length and days taken for first flowering. It also enhanced the physiological characters like chlorophyll content, light transmission ratio, total carbohydrate content in leaves and C: N ratio. The yield characters like percentage of fruit set, fruit length, number of fruits per tree, fruit yield per tree, average fruit weight, fruit volume, fruit diameter, seed and pulp ratio were also higher in the moderately pruned (30 cm) with 125 per cent RDF applied through drip fertigation. The interaction effect of moderate pruning (30 cm) with application of 125 per cent RDF through fertigation increased the quality characters i.e., total soluble solids, titrable acidity, ascorbic acid content, total sugars, reducing sugars, nonreducing sugars and pectin content in guava. The above treatment combination also recorded higher available soil and leaf nutrient status and B: C ratio. In conclusion of this study, it was inferred that moderate pruning (30 cm) along with application of 125 per cent RDF through fertigation was the best management strategy for getting higher productivity with higher B: C ratio (Rainy season 4.82 and Winter season 7.53). It can be recommended for effective and economic management practices for guava.