Kotoky, U.Saikia, Divyashree2023-10-062023-10-062018https://krishikosh.egranth.ac.in/handle/1/5810198525The present investigation entitled “Regulation of flowering in guava (Psidium guajava L) cv. Lucknow – 49” was conducted in the Experimental Farm and Laboratory, Department of Horticulture, College of Agriculture, Assam Agricultural University, Jorhat during 2016-2018. A total of 6 (six) treatments with four replications and two seasons (rainy and winter) were laid out in a Randomized Block Design. The treatments comprised of T1 – Naphthalene acetic acid (NAA at 100 ppm), T2 – Naphthalene acetamide (NAD at 40 ppm), T3 – Naphthalene acetamide (NAD at 60 ppm), T4 - Urea (2%), T5 – Urea (5%) and T6 – Urea (10%). All the treatments were applied during the flowering in the month of April, 2017 with the objectives to standardize the regulation of flowering and to study the efficacy of chemicals on growth, yield and quality parameters. During the period of investigation, the treatments showed varied response to flowering, fruiting, yield attributing characters, yield and quality of the fruits. Application of T3 (60 ppm NAD) significantly increased number of flowers (23.25) per branch, fruit set per cent (78.37%) and number of fruits per branch (19.75) in winter season during the experimental period. Reducing the fruit set per cent (16.14%) in rainy season, due to the spray of NAD at 60 ppm increased the production of superior quality fruits in the winter season. The yield attributing characters were significantly influenced by adoption of the treatments. The highest fruit length (8.04 cm), fruit girth (19.23 cm), fruit weight (162.07 g), fruit volume (144.10 cc) and lowest fruit drop (38.26%) were recorded under 60 ppm NAD (T3) in the winter season. Among the quality attributing characters, the highest juice content (48.45%), TSS (10.73oBrix), reducing sugar (3.74%), non-reducing sugar (3.10%), total sugar (6.82%), sugar acid ratio (45.46), pectin content (3.42%), ascorbic acid (264.18 mg/100 g) and the lowest titrable acidity (0.15%) were recorded under 60 ppm NAD (T3) in winter season. Studies on leaf nutrient status after the application of treatments indicateed that, the treatment T4 (2% urea spray) recorded the highest amount of nitrogen (1.52%) and in phosphorus; the highest (0.41%) was obtained by treating with 60 ppm NAD (T3). The plants sprayed with NAA at 100 ppm (T1) recorded the highest potassium of 0.36%. Evaluation of comparative economics revealed that, the highest benefit-cost ratio of 2.82 was obtained under T3 (60 ppm NAD) followed by T1 (100 ppm NAA) as 2.72. The lowest benefit-cost ratio of 2.42 was recorded in T4 (2% Urea spray). Thus, it can be concluded that, application of NAD at 60 ppm concentration applied in the rainy season found to be the most profitable treatment for improving the flowering, fruit production, yield and fruit quality in the winter season guava crop.EnglishThesis