In vitro GENOTYPE-ENVIRONMENT INTERACTION STUDIES IN CHILLI (Capsicum annuum L.)
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Date
1997
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Publisher
AAU, Anand
Abstract
Capsicum annuum L. is widely cultivated species of chillies in the world. India is leading producer and exporter of chillies at global level. For maintaining and elevating its position, there is need to increase productivity to meet the demands of the growing population as well as the export market. Genetic improvement of chilli crop through in. vitro techniques has been hindered due to lack of suitable protocol to regenerate plants from different explants and genotypes. Very few researchers have worked on hot red pepper and therefore little information is available on in vitro techniques and genotype-environment interaction of various locally grown chilli cultivars. The present investigation is therefore carried out at Tissue Culture Laboratory, Vegetable Research Unit, Gujarat Agricultural University, Anand during December 1994 to February 1997 to generate information regarding genotypeenvironment interaction on: 1) Direct organogenesis 2) In vitro rooting 3) Callusing 4) Somatic embryogenesis 5) Anther culture Direct organogenesis is an efficient tool for fast true to type multiplication of selected plants from breeding material; whereas in vitro rooting of nodal segment of old plants provide easy tool for multiplying spontaneous male sterile plants and other rare mutants. Somatic embryogenesis is an efficient means for multiplication of desirable heterozygous plants from breeding material at very high rate. Anther culture can help in developing cent percent homozygous inbreds in shortest period as compared to conventional inbreeding methods. In the present investigation, nine genotypes were used in the studies pertaining direct organogenesis, callusing and somatic embryogenesis whereas three genotypes were tried for iji vitro rooting of nodal segments from old plants and anther culture. Among different genotypes tried, Jwala gave better response for in vitro rooting, somatic embryogenesis and anther culture whereas S-49 produced higher number of shoots through direct organogenesis from cotyledon explant. California Wonder gave higher callus growth among all the genotypes tried. Studies indicate that Jwala was having better regeneration response among various genotypes tried and the regeneration response was found to be controlled genetically. Among various concentrations and combinations of growth regulators and basal medium tried in the present investigation, MS + 0.1 mg 1-1 NAA + 10 mg 1-1 BA was proved best for direct organogenesis whereas 50 mg 1-1 NAA shock for 24 hrs. followed by subculturing on half MS semi-solid medium was proved best for in. vitro rooting. Somatic embryogenesis was found better on MS + 7.5 mg 1-1 NAA, whereas low concentration of NAA (i.e. MS + 5.0 mg 1-1 NAA) proved superior for callusing. MS + 0.5 mg 1-1 2,4-T) + 1.0 mg 1-1 BA was superior for higher per cent callusing from anthers. In the present investigation, the media for callusing from hypocotyl and cotyledon (i.e. MS+5.0 mgl-1 NAA) and from anther (i.e. MS + 0.5 mg 1-1 2,4-D +1.0 mg 1-1 BA) was found suitable for all the genotypes tried. This was reflected in significant effect of medium on in vitro regeneration. Various aspects of genotype medium combination were also found very specific. The variety S-49 on MS + 0.1 mg 1-1 NAA + 10 mg 1-1 BA, and variety G-4 on 50 mg 1-1-1 NAA shock for 24 hrs. followed by subculturing on 5 MS semisolid medium was proved best for direct organogenesis and In vitro rooting respectively. For callusing California Wonder on MS + 12.5 mg 1-1 NAA and MS + 5.0 mg l-1 NAA was found best for hypocotyl and cotyledon explant respectively as reflected from their fresh and dry weights. Jwala gave highest number of embryoids on MS + 7.5 mg l-1 NAA whereas highest per cent callusing from anthers was obtained on MS + 0.5 mg 1-1 BA from the same genotype. Highly significant interaction of genotype and media was evidenced from the results. The results of all the experiment's indicated that there was no consistent performance of single genotype for all the aspects studied eventhough Jwala performed better for most of the aspects. This varied response indicate that loci influencing direct organogenesis may differ from the loci influencing in vitro rooting. This holds true for callusing, somatic embryogenesis and anther culture also. The studies also indicated that there is a need for specific exogenously supplied growth regulator for expression of genetic potential of a particular trait.
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Keywords
PLANT BREEDING AND GENETICS, AGRICULTURE, A STUDY