TARGETED INDUCED LOCAL LESIONS IN GENOMES (TILLING)-BASED MOLECULAR MUTAGENESIS AND SPEED BREEDING IN PAPAYA cv. ARKA PRABHATH FOR ENHANCING FRUIT QUALITY AND YIELD TRAITS
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Date
2022-12-28
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University of Agricultural Sciences, Bangalore
Abstract
The papaya cv. Arka Prabhath is an advanced gynodioecious cultivar developed at ICAR-IIHR, Bengaluru. The seeds were treated with various doses (0Gy, 50Gy, 100Gy, 150Gy, 250Gy and 500Gy) of gamma radiation to study the mutational influence on the
fruit quality and yield traits. The LD50 was noted to be at 250 Gy for gamma irradiations. The lowest plant height in T5 (26+cm) with 45 days of early flowering was observed in M1 generation. Early bearing family was H with 56 days, whereas family E showed dwarf
stature at first flowering among M2 mutants. In M4 mutant, early flowering was observed in Family H and C with 55 and 54 days meanwhile showed lowest error of variance. The shelf life studies, post harvest analysis and biochemical parameters were studied among all selected 36 mutant lines. Based on 14 to 16 days enhanced shelf life, quality fruit storage, pulp thickness, highest TSS of 14°brix, less post harvest loss in weight, good fruit cavity, length and width. Higher total soluble sugars, titratable acidity, ascorbic acid content carotene and lycopene content in the fruit pulp ten mutant lines were forwarded. In order to study the sequence variations, Single Nucleotide Polymorphisms (SNP’s) and insertions and deletions in fruit ripening genes viz., ACC-oxidase, ACC-synthase and ETR-1. Gene amplification of 10 selected mutants R12P17, R14P15, R16P18, R17P14, R1P7, R5P13, R7P2, R19P10, R21P15 and R25P14 of ACC-oxidase, ACC-synthase and Ethylene
receptor-1 resulted in 957bp, 1465bp and 2217bp fragments, these were cloned, plasmids were sequenced. The Multiple sequence alignments revealed several point mutations, SNP’s and insertions at various positions. These results confirmed the sequence various
is mainly due to induction of different doses of gamma radiation induced to seeds. These changes in morphological, physical and biochemical variations in plants and fruits may be due to induced mutation.