Correlation of Shape of Fruits, Cotyledons, and Seeds in Melons

Abstract

1. The correlation of shape of cotyledons with shape of fruits, of shape of seeds with shape of fruits, and of shape of seeds with shape of cotyledons was investigated in melons. 2. Coefficients of correlation were calculated by using shape indices. By employing the methods of analysis of covariance, coefficients were determined, not only for the total correlation of variations in shape but also for the correlation between varieties and for that within varieties. 3. Shape of cotyledons was significantly and positively correlated with shape of fruits in watermelons, the coefficients for the total correlation ranging from 0.40 to 0.75 and those for the correlation between varieties from 0.60 to 0.99. 4. There was no significant correlation of shape of cotyledons with shape of fruits in citrons nor in watermelon-citron hybrids. 5. Shapes of cotyledons were found to be significantly correlated with shapes of fruits in a small group of plants of Cucumis melo L. (r=0.27). 6. In 28 American varieties of watermelons, the mean shape indices of seeds were significantly correlated with mean shape indices of cotyledons (r=0.42) and with mean shape indices of fruits (r=0.60). 7. A significant change in the shape of watermelon cotyledons occurred as the seedlings grew, the relative length of the cotyledons increasing more rapidly than the width. 8. In many varieties of watermelons, and particularly in the Iowa Belle variety, fruit shape can be foretold from observations on the cotyledons. There is much greater accuracy in forecasting the mean shape of fruits of a variety or selection than in forecasting the fruit shape for an individual plant. Strains homozygous for fruit shape may be selected by observing the uniformity of cotyledon shape.