Influence of plant growth substances on reproductive growth, yield and fruit quality of pear (Pyrus communis L.) cv. Punjab Beauty

Under sub-tropical region, poor fruit set is a major constraint in semi-soft pears resulting in lower fruit yield. To study the effect of plant growth substances on fruit production and quality, the plants of pear cv. Punjab Beauty were sprayed with the plant growth substances viz., boric acid (200, 300 ppm), CPPU (5, 10 ppm), NAA (10, 20 ppm) and P-Ca (150, 300 ppm) at full bloom stage. Among all the applied treatments, boric acid @ 200 ppm proved to be most effective with maximum fruit set (6.91 %), fruit retention (59.9 %) and yield (57.8 kg/plant), while, maximum fruit weight (162.3 g) was observed with NAA (20 ppm). The highest internal fruit quality in terms of maximum TSS (12.4o Brix), TSS/acid ratio (53.4) and ascorbic acid (12.8 mg kg-1) was observed in 200 ppm boric acid. However, the total phenol (30.9 mg GAE/100 pulp) and flavonoid (36.1 mg CE/100 pulp) content was significantly higher with NAA (20 ppm). The plant growth substances reduced the polyphenol oxidase activity in fruits. Overall, the application of boric acid (200 ppm) resulted in improved fruit set, yield and quality in pear cv. Punjab Beauty.