Mutantes rin, norA, og c e hp em diferentes backgrounds genotípicos de tomateiro

Abstract

Rin, nor A , og c and hp mutants in tomatos with different genetic backgroundsAbstract -The objective of this work was to assess the viability of single and simultaneous use of rin, nor A , og c and hp as heterozygotes in tomato genotypes in order to improve post-harvest fruit quality. Eighteen genotypes differing in combinations among these loci in two backgrounds (Floradade and experimental background) were evaluated. Contrasts were used to quantify the effects of single and simultaneous application of mutant loci, in two different backgrounds, on the total and early fruit yield, fruit mean mass, fruit firmness, development of external fruit color, lycopene and beta-carotene fruit contents. The nor A and the rin alleles, used as heterozygotes in the FloraDade background, delayed the fruit softening and reduced lycopene and beta-carotene contents of mature fruit. All heterozygous combinations between rin and the mutants nor A , og c and hp increased fruit firmness. The effect of the rin + /rin nor + /nor A genotypes on fruit firmness was roughly the sum of the individual effects of each locus. The rin allele was more efficient than nor A to keep fruit firmness. The og c+ /og c and hp + /hp genotypes, singly or in combination, improved colour of rin fruits. The combination rin + /rin and nor + /nor A can be used in breeding for long shelf life tomatoes; however, genotypic backgrounds where fruit colour is less adversely affected should be sought or, alternatively, the colour mutant heterozygotes og c+ /og c and hp + /hp should be used.

Postharvest Conservation of Structural Long Shelf Life Tomato Fruits and With the Mutant Rin Produced, in Edaphoclimatic Conditions of the Southern State of Tocantins

“…According to Faria et al (2006), the fruit shape is determined by the ratio between the longitudinal and transverse lengths, being a mark to classify different tomato cultivars as to morphoanatomical group (Santa Cruz or Salada). Significant differences were found in Table 1 among the average of treatments, distinguished by the Scott-Knott (p = 0.05).…”

“…Araújo et al (2002) related the smallest water loss at post-harvest and the longest shelf life of the long shelf life tomato fruits attributed to the reduction of the peduncular scar size. According to Faria et al (2006) the reduction of peduncular scar of the fruits may be due to both the effects of allele mutants and the genetic background. Leal and Shimoya (1973) state that this characteristic is directly related to the decay process of the fruit.…”

“…From these results, the favorable contribution of long shelf life rin genotypes on the increment of days to reach the limit value of firmness, is being a characteristic that regardless of the weather condition where the fruit is produced, requires only that the fruit is harvested at stage 1 of maturation. Faria et al, (2006) report that the advantage that the genotypes carrying the mutant allele present on the normal genotype is quite significant from the standpoint of post-harvest storage. For marketing, this aspect starts to have greater importance when the fruits are produced in locations distant from the places of consumption.…”

“…Regarding the use of ripening mutants, the allele rin (ripening inhibitor) is the most used allele in modern cultivars (Cá et al, 2006). These alleles delay ripening and prolong shelf life, interfering mainly on the firmness and carotenoid pigments synthesis, in addition to being useful for a better understanding of the processes which regulate the maturation and the development of new cultivars with longer shelf life (Dias et al, 2003;Faria et al, 2006;Cá et al, 2006).…”

Biology and genetic engineering of fruit maturation for enhanced quality and shelf-life

“…Although knowledge of the mechanism of fruit softening has grown in recent years, it has proven especially difficult to establish the relationship between specific aspects of cell wall metabolism or architecture and their relationship to changes in tissue firmness [19,21]. Similarly, it has also been difficult to establish the fine regulation of genetic elements that produce a range of effects depending on the genetic background in which they are introduced [22]. The regulation of texture and shelf-life is clearly far more complex than was previously envisaged and so new approaches are needed, including the inclusion of observations in species beyond the traditional tomato experimental model [23]; a better understanding of the relationship between changes in the textural properties of specific fruit tissues, intact fruit 'firmness' and shelf-life; and more comprehensive models of the biochemical and physiological elements that contribute to fruit 'firmness'.…”