Abstract:
The investigation “Selection for mosaic resistance in pumpkin (Cucurbitamoschatapoir)” was conducted at the College of Horticulture, Vellanikkara, Thrissur during November 1990 – April 1992. The high yielding and locally adapted variety Ambili was sown at bimonthly intervals to study the seasonal influence on mosaic incidence, vector population and yield. Incidence of yellow vein mosaic, pumpkin mosaic, bottle gourd mosaic, watermelon mosaic and cucumber mosaic were observed in crops sown during different months. Incidence of yellow vein mosaic and population of whiteflies (BemisiatabaciGenn.), the vector of yellow vein mosaic, were positively correlated with temperature and negatively correlated with rainfall and relative humidity. Fruit yield and contributing characters were significantly influenced by different dates of sowing and sowing in October was found to yield maximum because of the delayed incidence of mosaic.
From the study of P1, P2, F1, F2 , BC1 and BC2 generations of the cross involving mosaic susceptible Ambili and resistant CM 214 (Nigerian Local), resistance to yellow vein mosaic was found to be governed by a single dominant gene and pumpkin mosaic by a single recessive gene. Silvery leaf trait was found to be dominant and governed by two genes. The study resulted in the identification of five promising selections from the segregating populations.
Attempt was also made to improve the line CM 214 through selection. Improvement could be made in fruit set, seeds per fruit, hundred seed weight and seed germination. Germination percentage of CM 214 was significantly increased by removal of seed coat before sowing. Superior progenies of CM 214 were also selected for further improvement.
