Yield and fruit quality evaluation in husk tomato autotetraploids (Physalis ixocarpa) and diploids.

Tomatillo (Physalis ixocarpa Brot.) is a native species of Mexico and Central America, ranking fourth in cultivated area among main vegetables in Mexico. The objective was to evaluate and select, husk tomato autotetraploid and diploid populations for yield and fruit quality. Five autotetraploid populations with higher yields and fruit quality, previously selected for an assessment study of autotetraploids formed by the action of colchicines were used. The five autotetraploid populations were compared with four diploid populations with outstanding agronomic traits in the source regions. The populations were established under a completely randomized block design with four replications. The studied traits were: Fruit yield, fruit weight, fruits per plant, equatorial and polar fruit diameter, total soluble fruit solids, fruit firmness, pH and vitamin C content. The diploids showed the following characteristics; fruit yield=1.809 kg plant -1 ; number of fruits per plant=56.227. The autotetraploid presented fruit yield = 1.688 kg plant -1 , number of fruits per plant = 60.776. Analysis of variance showed significant differences between locations, and between populations for most variables, indicating that they responded in a different way to the environments and to both ploidy levels under study. When comparing the group of four diploid populations with the five autotetraploids, significant differences (p ≤ 0.01) were found for polar and equatorial diameter of fruit, and fruit firmness (p ≤ 0.05), for vitamin C, however when comparing the Rendidora diploid with the group of five autotetraploids, significant differences were found (p ≤ 0.01) for fruit weight, fruit equatorial and polar diameters, fruit firmness and vitamin C content, and (p ≤ 0.05) for fruit yield per plant and number of fruits per plant. The chromosomal duplication in husk tomato Physalis ixocarpa contributed to the change in the shape of the fruits which flattened at the poles with the presence of gaps between the endocarp and the mesocarp. The vitamin C content in autotetraploids was enhanced which contributed to the improvement of the fruit nutritional quality. It is noteworthy that the evaluated autotetraploids are materials needing a process of selection and chromosomal stabilization in order to achieve the full expression of their genetic potential.