Intergeneric crossing, intervarietal progeny evaluation and mutagenic studies in papaya (Carica papaya L.)

Abstract

The investigation on “Intergeneric crossing, inter-varietal progeny evaluation and mutagenic studies in papaya (Carica papaya L.)” was conducted at Division of Fruit crops, Indian Institute of Horticulture Research, Bangalore during 2010-2011. A breeding programme was undertaken using Carica papaya var. Arka Surya and Vasconcellea cauliflora with a view to raise progenies resistant to Papaya ring spot virus (PRSV). An attempt was made to break the barrier using different chemicals like (sucrose 5% + boric acid 0.5% + calcium chloride 0.1%). Among the different chemicals used, boric acid 0.5% resulted in good fruit set (96.2%). Final fruit retention till harvest (42.8) and seed recovered per fruit (178.6) were maximum in the case of sucrose 5%. Germination was recorded for the seeds treated with boric acid 0.5% (1.2%). Selfed progenies of gynodioecious hybrids Arka Surya and Arka Prabhath were evaluated for morphological and fruit traits. Variability was found within the progenies due to different genetic constitution of female and hermaphrodite plants in the population. However, quality of the fruits did not differ much. To create variability for plant height and other characters in the varieties Arka Surya and Arka Prabhath chemical mutagen, EMS was used along with KNO3 to increase the mutagen. LD 50 was observed at 0.3 per cent EMS. Early germination and maximum germination per cent were observed in control. EMS at 0.2 per cent along with KNO3 can bring about dwarf statured plants. In the M0 generation, many morphological abnormalities were observed which shows the possibility of excellent variability in advanced generations.