The effects of light exposure on colour development in the blush pear ‘ANP-0534’

Pear breeding programs throughout the world have released new fresh market cultivars that are premium quality and aim to increase world consumption of pears. Red colour of the fruit peel is a key quality requirement of many of the new cultivars. The degree of red coloration is determined by the concentration and composition of anthocyanins in the peel of pears. Biosynthesis of anthocyanins in plant tissues either requires or is enhanced by light. During this experiment, the effect of artificial shading on the red colour development of newly bred ‘ANP-0534’ pear was investigated. Six treatments were applied: a control treatment and five artificial shading periods which differed in duration and timing. Sample fruit were harvest 124 days after full bloom (DAFB). Peel colour was measured during the experiment. Red colour in the control treatment increased substantially between 21 and 42 DAFB, and thereafter gradually increasing in red colour until the last period where the rate of increase was highest. No red colour development was observed when fruit were artificially shaded from 21 until 105 DAFB. Artificial shading did not affect the maximum red colour when applied for 3-week periods between 21 and 84 DAFB. Later shading and longer periods of shading resulted in lower red colour at harvest. Maximum red colour occurred at the end of the season which is favourable and can make ‘ANP-0534’ a novel cultivar compared to other blush or fully red cultivars. The implications of these results in terms of managing fruit exposure to light are discussed.