Pre-Harvest Fruit Splitting of Citrus

Abstract

Under specific conditions, the fruit on citrus trees will split open. The damaged fruit is unmarketable and provides a habitat for fungal and insect pests that can reproduce and then damage currently marketable fruit. Losses of 30 to over 50 percent of the crop are possible with some cultivars. This is a physiological disorder that starts with nutrient imbalances at flowering that result in mechanically weak areas in the rind. These rupture if interior parts of the fruit expand faster than the peel can stretch. The disconnect between problem initiation and symptom expression provides many challenges to experimental designs and interpretation. Consequently, no solution has been found despite over a century of research into the problem. This is also a problem for growers because they can only see the problem after it is too late to correct. Our goal is to define the problem and highlight successes and failures in finding a solution. The review should help direct continuing research and provide information to extension personnel to help guide growers towards productive solutions.

Managing Fruit Splitting in Florida Citrus

“…The mandarin in the lefthand column has a closed stylar end (at the arrow tip). Credits: Krajewski et al (2022) maturation. In this stage, a rapid influx of water into the pulp increases the severity of splitting.…”

“…The mandarin in the lefthand column has a closed stylar end (at the arrow tip). Credits:Krajewski et al (2022)…”

“…Closeup of scarred area (D)shows slight abnormalities below scar (bracket). Credits:Krajewski et al (2022)…”

Physiological Mechanisms of Citrus Fruit Cracking: Study on Cell Wall Components, Osmoregulatory Substances, and Antioxidant Enzyme Activities

“…Citrus belongs to the subfamily Aurantioideae and family Rutaceae and represents the world’s most widely grown and most productive fruit genus [ 1 , 2 ]. Fruit cracking is a physiological disorder in citrus fruit development that occurs in various citrus varieties, such as mandarins ( Citrus reticulata ), navel oranges ( Citrus sinensis ), and mandarin hybrids ( Citrus reticulata × Citrus sinensis or Citrus reticulata × Citrus paradise ), with some citrus varieties having a fruit cracking rate of up to 50% or more, resulting in serious economic losses [ 3 , 4 , 5 , 6 ]. ‘Mingrijian’ (M), also referred to as ‘Asumi’, originated in Japan.…”