Genotype-environment interaction on the density of peach buds cultivated in a humid subtropical climate

Abstract

Studies on the interaction of genetic and environmental effects on floral morphogenesis in peach trees grown in humid subtropical climate provide important information related to adaptation and for assisting in the selection of new cultivars. This study aimed to verify the genetic and environmental effects and to identify peach tree genotypes with greater shoot length, vegetative bud, flower bud density adaptability and stability under humid subtropical climate conditions. Twelve peach tree genotypes were evaluated over a period of eight years, during the growing season (2006/07 to 2013/14) in Pato Branco-PR, Brazil. Data were collected for shoot length (SL), flower bud density (FBD) and vegetative bud density (VBD), as well as temperature, humidity and precipitation. For the analysis of adaptability and stability we used GEE Biplot methodology. SL was influenced by the temperature and relative humidity. Increased exposure time to temperatures below 20 °C and above 30 °C, high thermal amplitude and relative humidity of less than 50% reduced shoot growth. VBD and FBD were predominantly controlled by the genetic factor. For VBD, the genotypes ‘Cascata 1055’ and ‘Conserva 681’ were the most adapted. For FBD, the genotypes ‘Cascata 1055’, ‘BRS Bonão’, ‘Conserva 681’, ‘Cascata 967’ and ‘BRS Kampai’ presented better adaptability. The genotypes more adapted to the FBD can be recommended for cultivation in the humid subtropical climate, since they also present greater stability in the production of fruits, independently of the meteorological conditions that occur during the vegetative and reproductive season.

Response of peach tree leaf area to seasonal variation in tropical climate

“…The cv. 'BRS Kampai' presented a smaller difference between the variables of L, W and LF between the periods evaluated, as its vegetative development behavior is more stable to the environment variation (Penso et al, 2018).…”

“…The occurrence of a number of hours with temperatures between 25-30 °C and even above 30 °C (Figure 1 B), can invalidate the chilling accumulation effect of the buds, but they help in the requirement of heat so that the growth and development of the structures like fruits, shoots and leaves can occur. The occurrence of high temperatures can lead to an expressive increase in the growth and vegetative development of plants (Penso et al, 2018), considering that there is water availability in the soil and air. This can be observed in the second evaluation period, when there was a combination of high-temperature factors and water availability ( Figure 1B, 1C e 1D), vegetative growth, consequently the development of the leaf area (Table 1).…”

“…The absence/or lower probability of frosts during the winter in warmer climate areas and dormancy management technologies allows the anticipation of harvest in a period, of which there is a low fruit supply in the market, producing greater profit (Barbosa et al, 2010). However, due to the differentiated climate in these areas, there are plant management problems that can lead to significant changes in the developmental, physiological and anatomical behavior of the plants (Penso et al, 2018). The development of leaves of peach trees grown in tropical regions is submitted to novel environmental conditions that may associated with physiological and developmental behavior of the plant as a whole, which on the same hand, is different from the expected for traditional cultivation regions (Larbi et al, 2015).…”

Development of Peach Flower Buds under Low Winter Chilling Conditions

“…The expansion of new areas allows the prospect of an increase in world production in the future [5][6][7]. However, some of these areas have little winter chilling, and some of them have previously been considered marginal, presenting cultivation limitations mainly due to the lack of winter chilling but also due to the instability of environmental conditions among years and locations [8,9]. Such characteristics may cause high yield oscillations hindering the agroclimatic zoning for new cultivars.…”

“…Different strategies have been used to expand peach cultivation to subtropical and tropical zones with low winter chilling accumulation, including the introduction of new low-chilling cultivars from breeding programs [17], and the use of cultural practices such as the application of dormancy breaking agents, e.g., hydrogen cyanamide, and hydric deficit [6,13,[18][19][20][21]. However, problems regarding fruit set and production stability persist, possibly because they are associated with inadequate flower formation resulting from alterations during the different phases of flower development [9].…”