CARBON ISOTOPE DISCRIMINATION IN MANGO LEAVES UNDER SALT STRESS

ABSTRACT The aim of this study was to evaluate the response of mango plants ( L) ‘Mangifera indicaTommy Atkins’ cultivar to different NaCl concentrations. In this experiment, plants were grown in pots with washed sand and nutrient solution with 0, 10, 20 and 30 mM NaCl for 120 days. After this period, young leaves from the last growth spurt were harvested in a randomized block design, dried at 65 °C for 72 h and ground in a ball mill. Samples were dried again in an oven at 60 °C for 24 h and then the relative abundance of 13C and 12C isotopes was determined using mass spectrometer Sercon 20-20 isotope ratio model. Data were used to determine the carbon isotopic discrimination (?). It was concluded that ‘Tommy Atkins’ mango trees submitted to 30 mmol L-1 NaCl discriminated less 13C, which may be an indication of salt stress in these plants

Quantitative trait locus mapping associated with earliness and fruit weight in tomato

ABSTRACT The flowering time is regarded as an important factor that affects yield in various crops. In order to understand how the molecular basis controlling main components of earliness in tomato (Solanum lycopersicum L.), and to deduce whether the correlation between fruit weight, days to flowering and seed weight, is caused by pleiotropic effects or genetic linkage, a QTLs analysis was carried out using an F2 interspecific population derived from the cross of S. lycopersicum and S. pimpinellifolium. The analysis revealed that most of the components related to earliness were independent due to the absence of phenotypic correlation and lack of co-localization of their QTLs. QTLs affecting the flowering time showed considerable variation over time in values of explained phenotypic variation and average effects, which suggested dominance becomes more evident over time. The path analysis showed that traits such as days to flowering, seed weight, and length of the first leaf had a significant effect on the expression of fruit weight, confirming that their correlations were due to linkage. This result was also confirmed in two genomic regions located on chromosomes 1 and 4, where despite showing high co-localization of QTLs associated to days to flowering, seed weight and fruit weight, the presence and absence of epistasis in dfft1.1 × dftt4.1 and fw1.1 × fw4.1, suggested that the linkage was the main cause of the co-localization

POSTHARVEST CONSERVATION OF STRUCTURAL LONG SHELF LIFE TOMATO FRUITS AND WITH THE MUTANT RIN PRODUCED, IN EDAPHOCLIMATIC CONDITIONS OF THE SOUTHERN STATE OF TOCANTINS

The high temperature of growth environment can affect the postharvest quality of tomato fruits. In this situation, an alternative for the farmers is the use of hybrid cultivars that produce long shelf life fruit with longer postharvest shelf life when compared to normal varieties of fruits. The objective of this research was to compare the postharvest conservation of fruits of structural long shelf life tomato hybrids and with the mutant rin. The fruits evaluated were from fifteen tomato genotypes produced under the edaphoclimatic conditions of the southern State of Tocantins, being four of them long shelf life type hybrids (with rin allele) which were: Tyler, Rebeca, Carmem and AF 13527; nine of them structural long shelf life hybrids: Lumi, Débora Max, Michelli, Tammy, AF 12525, AF 11097, AF 13363, AF 13364 and AF 13525; and two normal fruit cultivars: Santa Clara and Drica. The fruits were harvested at the breaker stage and stored in a controlled environment (20 °C and relative humidity of 60%). The half-life firmness of fruits of genotypes with a structural genotypic long shelf life background ranged from 6.25 to 13.44 days for the genotypes Tammy and AF13525, respectively, not differing from the long shelf life genotypes with rin allele. Despite the fact that daytime temperatures are higher than those recommended for the tomatoes crops, it was observed that if the fruits are stored in appropriate conditions (20 °C and relative humidity of 60%), the color and firmness of the fruits with a long shelf life genotypes with rin allele and structural genotypic background evolve more slowly than the fruits of normal genotypes. Under these conditions, it took the fruits 7 to 8 days to acquire a red color on more than 80% of the surface after being harvested