Physical and biochemical changes in guava (Psidium Guajava L.) during various stages of fruit growth and development

Abstract

Physiological and biochemical changes during fruit growth, development and maturity of eleven genotypes of guava fruit were studied at 30, 60, 90, 105, 120 and 127 days after fruit set (DAFS). Fruit weight, length and diameter of guava fruit increased continuously from the initial stage of fruit development till maturity and ripening in all the genotypes. The increases in fruit weight and diameter were comparatively more between 30 to 60 DAFS and 90 to 127 DAFS than 60 to 90 DAFS where the increase in fruit weight and diameter was slow in most of the genotypes. However, RCG-1, RCG-2 and RCG-3 showed the continued rapid increase in fruit weight upto 120 days and thereafter the rate of increase was quite slow. A gradual increase in total soluble solids (TSS) was observed in all the genotypes throughout development and ripening stage of the fruits. However, the amount of total titratable acidity increased steadily in the beginning upto 105 days after fruit set in most of the genotypes except RCG-1, RCG-2 and RCG-3 which showed upto 90 days only and afterwards there was a continuous reduction till ripening. The fruits showed continuous and progressive increase in TSS: acid ratio from 30 DAFS till maturity and ripening in all the genotypes except RCG-11, RCGH-1 and RCGH-7 that showed from 60 DAFS. Based on the present findings, days taken from flowering to harvest maturity (>105 days), TSS (>9.50%) and TSS: acid ratio (>15.00) were some of the parameters for judging the maturity indices of genotypes like RCG-1, RCG-2 and RCG-3. Similarly, days taken from flowering to harvest maturity (>110 days), TSS (>10.50%), TSS: acid ratio (>21.00) and fruit skin colour (whitish green) for RCGH-1 were some of the parameters for judging the maturity indices. Whereas, other genotypes were also exhibited the variation for days taken from flowering to harvest maturity (>120 days), skin colours, TSS (9.20-11.00%) and TSS: acid ratio (13.50-23.50).