Obtenção de seleções de araçazeiro amarelo oriundos de progênies de plantas do sul do Rio Grande do Sul

Abstract

The objective for this research work was to obtain promising selections with potential to develop new cultivars of yellow cherry guava aiming future commercial fruit production in the South of Rio Grande do Sul. At the present there are only two cultivars released and recommended by Embrapa Clima Temperado, to be grown in this area, which are “Ya-cy” (yellow) and “ Irapuã” (red). Thirty four genitors were selected in natural conditions in this region. The genitors were selected considering characteristics such as: productivity; fruit quality; and apparent good sanitary conditions of the trees. Samples of fruits were collected from 34 genitors and were evaluated about their: appearance (size, form, sanity); number of seeds per fruit; weight of 100 seeds; and the percentage of plantlets emerged number from seeds of each genitor. The plantlets emergency varied from 41% to 88%, which due to the high number of seeds per fruit was not considered a limiting factor for progeny selection. The progenies were evaluated in a field experiment according to a randomized complete blocks (five blocks having 15 plants of each progeny). In that experiment the progenies were evaluated about their blooming and fruit ripening periods; and their trunk and height after one and a half year planted in the experiment. The harvested fruits from the progenies were kept in a common freezer and after evaluated about: total soluble sugars; titratable acidity; pH; weight of 50 seeds; average of seed number per fruit; maximum diameter and fruit length; and measure of epicarp + mesocarp of the fruits. There were significant differences among progenies in trunk diameter and plant height. However there was no significant relationship between trunk diameter and plant height (p≤0,05). In the first productive cycle (2015/16) the bloom phenology was very difficult to register, since the young trees (only 8 months in the orchard) had spread blooming and the new shoots emitted new flower buds almost continuously (flower buds are produced in the shoots of the current growing season). Besides that, the young trees produced small number of flowers, which turns the phenology phases more difficult to define. In the first productive cycle (2015/16) the blooming occurred from the end of July to the end of November and fruit ripening (harvesting period) occurred from the beginning of January to the beginning of June. Statistics differences occurred among progenies regarding to fruit number and fruit yield per tree. There was relationship of fruit diameter and fruit length in that first productive cycle. In the second producing cycle only total number of fruits per tree was evaluated. There were significant differences (α≤0,05) among progenies regarding to fruit number per tree. Five new selections were obtained based on: plant fruit productivity; and fruit quality (size, shape, flavor, seed size; and pulp yield).