GENOTYPIC DIFFERENCES IN SHOOT MULTIPLICATION AMONG FIVE CITRUS ROOTSTOCKS IN VITRO

The present study aims at developing optimal media for different cultivars of Citrus namely, ‘Rangpur’ lime, ‘C 35’ citrange, ‘Troyer’ citrange, ‘Swingle’ citrumelo and ‘Alemow’ macrophylla.
Cultures from adult field-grown trees were established from nodal stem segments for axillary proliferation.
The single node segments were surface-sterilized and cultured on Murashige and Skoog (MS medium; 1962) medium.
The shoot cultures obtained were used as explants to investigate the effects of various media constituents necessary for growth.
Among the media constituents, cytokinins played a crucial role in shoot proliferation and thus were a prerequisite for the shoot multiplication media in all the cultivars.
In case of ‘Alemow’ macrophylla, a synergistic effect of auxins and cytokinins was observed.
The effect of sucrose concentration was also variety-dependent and significantly affected the production of axillary shoots, with either 3% or 4% being the optimal concentration depending upon the rootstock.
Moreover, the influence of gelling agents also varied with each cultivar.
For ‘Rangpur’ lime, gelrite (0.2%) was the optimum gelling agent whereas agar-gel (0.4%) was the best for the remainder four varieties.
Among the five rootstocks tested, shoot proliferation rate was highest in ‘Rangpur’ lime and lowest in ‘Alemow’ macrophylla.
The results demonstrate that genotypic differences played a significant role in the induction and growth of axillary shoots.
Thus, in this study we were able to identify and optimize the most effective multiplication media for each cultivar, which is a necessary step to develop an efficient micropropagation protocol.

I International Symposium on Biotechnology of Fruit Species: BIOTECHFRUIT2008

S. Sen, V. Dhawan

Citrus, enhanced axillary branching, micropropagation, shoot quality, cytokinins

https://doi.org/10.17660/ActaHortic.2009.839.3