Agricultural Reviews
Year : 2000, Volume : 21, Issue : 1
First page : ( 1) Last page : ( 15)
Print ISSN : 0253-1496.

An analysis on citrus flowering – A review

Srivastava A.K., Singh Shyam, Huchche A.D.

National Research Centre for Citrus, Amravati Road, Nagpur - 440 010, India.

Abstract

The flowering in Citrus is recurrent under tropical and subtropical conditions unless synchronized into a well-defined period of concentrated bloom by external conditions. In sub-tropical areas during the winter months, air and soil temperature falls below about 15°C for several months which causes growth to cease for three to four months. Such a cessation of growth induces greater tolerance to frost damage and causes changes within the buds which induce flowering when subjected to warmer temperatures. In a typical subtropical climate with cool winters, citrus tends to bloom profusely in the spring and set only one major crop which matures in late fall, or winter, or even the following spring depending on variety and seasonal temperature regime. Flower formation in Citrus species is promoted by drought or low temperature, followed by restoration of climatic conditions favourable for growth. The flowering can be induced by low temperature or water stress and inhibited by applied gibberellin. Application of GA₃ inhibited the drought induced flowering in Eureka lemons, while growth retardant cycocel could replace water stress treatment and promoted flowering in lemons. The chemical compounds such as CCC, SADH and benzothiazole were observed to promote flowering in lemons. Paclobutrazol, an inhibitor of GA biosynthesis, has shown a good promise both as a soil drench and foliar sprays in cultivars like Satsuma and Nagpur mandarin. The other compounds such as ethrel and NAA have been practised during heavy “on year” to minimise the recurrence of alternate flowering.

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