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A melon (Cucumis melo L.) genomic library of near-isogenic lines derived from the cross between the Spanish cultivar Piel de Sapo and the exotic accession PI 161375 has been evaluated for fruit quality traits in four different locations. Traits evaluated were fruit weight, soluble solids content, maximum fruit diameter, fruit length, fruit shape index, ovary shape index, external color, and flesh color. Among these traits, soluble solids content showed the highest genotype × environment interaction, whereas genotype × environment interactions for fruit shape and fruit weight were low. Heritability was high for all traits except soluble solids content, with the highest value for fruit shape and ovary shape. Ten to 15 quantitative trait loci were detected for soluble solids content, fruit diameter, fruit length, and fruit shape; and four to five for ovary shape, external color, and flesh color. Depending on the trait, between 13% and 40% of the detected quantitative trait alleles from PI 161375 increased the trait, and between 60% and 87% of them decreased it, resulting in some PI 161375 alleles of interest for breeding. Most of the quantitative trait loci detected in previous experiments could be verified with the near-isogenic line population. Future studies with the melon near-isogenic line genomic library will provide a better understanding of the genetic control of melon fruit quality in a wider context related to agronomy, genetics, genomics and metabolomics studies.

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The effect of different irrigation strategies on the fruit quality at harvest and during storage at 1• C of 'Búlida' apricots (Prunus armeniaca L.) was studied. Irrigation treatments consisted of a control irrigated at 100% of crop evapotranspiration (ETc) throughout the season, and two deficit irrigation treatments consisting of continuous irrigation at 50% of control, and regulated deficit irrigation (RDI) at 100% of ETc during the critical periods (second rapid fruit growth and early post-harvest) and at 25% during the rest of the season. Fruits at harvest from both deficit irrigation treatments showed higher values of total soluble solids (TSS), titratable acidity and hue angle (h • ) than control fruits, whereas their diameter, fresh weight, firmness and maturity index values were similar to those in the control. During the first 10 days of the 30-day chilling storage period, higher TSS and h• values were found in deficit irrigated fruits, whilst the other parameters were similar for all treatments. Weight loss and fungal attacks (mainly Rhizopus sp. and Monilinia sp.) during a subsequent retail sale period of 4 days at 13• C were the lowest in RDI. Deficit irrigation was demonstrated to be commercially advantageous for keeping fruit quality, saving considerable amounts of water.

Four of the most widely produc.ed tultivars of muskmelon in Spain (' 'Piel de Sapo, " "Amarillo, " "Galia '' and "Tendral '7 were characterized using the quality factors at harvest of: weight, calibers, shape, peel thickness, edible portion, ,firmness, soluble solids content, p H , titratable acidity, reducing and nonreducing sugars, formol index, mineral nutrients and respiration rate. "Piel de Sapo " fruits were highest in weight, caliber and edible portion and were the most oi~al shaped. "Amarillo" fruits were highest in soluble solids and nonreducing sugars and had the lowest respiration rate. "Galio '' offered the lowest weight, pulp$rmness and acidiiy and high values of reducing and nonreducing sugars and mineral nutrients, \tith the most sphericul shupe. 'Tendral "presented highest values of peel thickness, pulp firmness acidity and respiration rate and the lowest values of soluble solids and minercrl nutrients.

A collection of melon (Cucumis melo L.) near-isogenic lines (NILs) derived from the cross between the Spanish C. melo cultivar Piel de Sapo (PS) and the exotic Korean accession Shongwan Charmi [SC (PI161375)], was used to study the genetic control of a large number of melon fruit quality traits, including morphological, external appearance, texture, flavor, and the overall differences between NILs and PS that might be detected by consumers with a triangle test. Heritability was significant for all the traits, being >0.5 for the whole area of the longitudinal section of the fruit, flesh proportion, skin lightness color, hue angle coordinate of flesh color, and flesh-extractable juice. NILs were classified by principal-component analysis. The first principal component (22% of the variation) was affected mostly by morphological traits, the second component (10%) was influenced by internal and external morphology pattern and color, and the third component (9%) was controlled mainly by flavor traits. An average of 5.6 quantitative trait loci (QTL) per trait were identified (range, between 1 and 12 QTL; 134 QTL in total). In most cases, allele effects with opposite actions were detected. A substantial number of QTL may be good candidates to introduce new quality attributes in modern melon cultivars.

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