Strategies for breeding a new greenhouse crop, the pepino (Solanum muricatum Aiton)
The introduction of pepino (Solanum muricatum Aiton) as a new greenhouse crop relies on the development of clones that produce high fruit yields with an increased soluble solids concentration (SSC). We have evaluated two breeding strategies aimed at obtaining new, improved clones of this heterozygous vegetatively propagated crop: selection in the segregating generation F1 (hybrids) or in the first generation of selfing (selfings). We recorded the total yield, SSC, fruit weight, shape, firmness, titratable acidity and ascorbic acid concentration in seven populations of hybrids and in five populations of selfings. Four populations of clonal replicates were used to estimate environmental variability. Total yield and its heritability were higher in the hybrids than in the selfings. Expected responses to selection showed that it might be possible to select clones with a yield higher than 80 t ha−1 with selection pressures lower than 5% in some hybrid populations. Heritabilities for SSC were moderate, but clones with a SSC higher than 9.0 °Brix could be selected. We also found an important variation in the other characters studied, indicating that improved clones could be selected for all of them. Values for genotypic correlations between characters were very variable. In most hybrid populations, however, we did not find negative genotypic correlations between yield and fruit quality characters. Our results indicate that new hybrid clones of pepino that exceed present clones in yield and fruit quality might be obtained. Key words: New crops, plant breeding, clonal propagation, hybrids, selfings