Litchi and Longan: Botany, Production and Uses

One of the main disorders that widely limit fruit quality and quantity is fruit cracking or splitting that is observed on the fruit skin and flesh in the preharvest phase. Besides, cracking can occur during postharvest in some fruits, mostly attributable to the environmental conditions of storage. Value of cracked fruits is reduced and these fruits are not marketable because of the poor fruit quality. Many fruits such as apple, sweet cherry, grape, plum, pomegranate, grape, persimmon, litchi, avocado, pistachio, citrus, banana as well as tomato can crack or split. There are many factors that influence fruit cracking. In this work, genetic, morphological, environmental and physiological aspects of fruit cracking are reviewed. Under the same environmental conditions, fruits from different cultivars show differences in cracking susceptibility. Some correlations have been observed between susceptibility of fruit cracking and some fruit traits (fruit shape, fruit size, fruit firmness; anatomy and strength of the fruit skin, stomata in fruit skin, cuticular properties, osmotic concentration, water capacity of the fruit pulp and growth stage of the fruit). Also, orchard management (such as irrigation and nutrition) and environmental condition (such as temperature, wind and light) can influence fruit cracking. Besides, fruit cracking is quantitative trait and is controlled by several genes. The best way to reduce fruit cracking at present would be a suitable orchard management that takes into account and try to minimize stress of the water, nutrition and physiological factors that contribute to fruit cracking. Also, the most resistant cultivars to fruit cracking that have desirable fruit quality can be selected for cultivation.

Physiological and genetic factors influencing fruit cracking

SummaryModerate day/night temperatures (20/15° v. 15/10°C) increased vegetative growth and reduced flowering in the seven litchi cvs Tai So, Bengal, Souey Tung, Kwai May Pink, Kwai May Red, Salathiel and Wai Chee. At higher temperatures (25/20° and 30/25°C), vegetative growth was promoted further and flowering eliminated. Temperature also influenced the type of inflorescence formed. More leaves were formed on the panicles of trees growing at 20/15° than at 15/10°C. All terminal shoots on all cultivars produced panicles at 15/10°C. The relative order for the amount of flowering at 20/15°C was: ‘Wai Chee’>‘Salathiel’>‘Kwai May Pink’>‘Tai So’>‘Bengal’>‘Souey Tung’>‘Kwai May Red’. Cultivars which were vigorous at high temperatures produced fewer panicles at 20/15°C and fewer leafless panicles at 15/10°C. Only small differences were observed in the leaf water potential and the nutrient status of the shoots at different temperatures. Vigour and flowering of the cultivars in the glasshouse generally reflected fi...

Effect of temperature on growth and flowering of litchi (Litchi chinensis Sonn.) cultivars

Lychee nutrition: A review

Fruit development and abscission in 'Mauritius' lychee (Litchi chinensis Sonn.) were studied over three consecutive seasons. Each season, two distinct abscission periods were observed. The first started at the end of full female bloom and continued for ≈ 4 weeks. Of the initial number of female flowers, 85 % to 90 % abscised during this period. The second period began after a lag period of ≈ ≈ 1 week and lasted ≈ 2 weeks. About half of the remaining fruitlets abscised during this wave. AU of these fruitlets contained an embryo. The second wave coincided with a period of rapid embryo growth and endosperm loss. Tipimon (a commercial product containing the triethanolamine salt of the synthetic auxin 2,4,5-TP) consistently and significantly increased marketable fruit yield when applied between the two abscission periods. Chemical name used: 2,4,5 -trichlorophenoxy propionic acid (2,4,5 -TP).

/pdf/mauritius-lychee-fruit-development-and-reduced-abscission-2ks970q1d0.pdf

C.M. Menzel

Papers

The pattern and control of reproductive development in lychee: A review