Microsporogenesis of Apricot Cultivars in Hungary

Abstract

Like all phenological processes, microsporogenesis is mainly determined genetically, but its phenotypical expression is greatly influenced by environmental factors, particularly the temperature. During the 3-year experimental period, the process of microsporogenesis was examined in eight apricot cultivars originated in North America and in Romania. The Hungarian cultivar ‘Gönci magyar kajszi’ was used as the control. Based on the results it was possible to rank the cultivars in terms of their microsporogenesis schedule. The same order was found in all three years. This order also indicates the yield reliability of the cultivars. Endodormancy ended between January 10th and 25th in the buds of the earliest cultivar ‘Pinkcot’, but not until February 5-10th in the latest cultivar ‘Harlayne’. Three of the cultivars had faster flower bud development than the control, in the order ‘Pinkcot’, ‘Orange Red’ and ‘Harcot’. Growing these cultivars thus involves greater risk than for ‘Gönci magyar kajszi’ in Hungary, due to their rapid winter flower bud development. Some cultivars found to have slower flower bud development than ‘Gönci magyar kajszi’; ‘Litoral’, ‘Harogem’, ‘Comandor’, ‘Sirena’ and ‘Harlayne’ – thus these cultivars can be grown more reliably.

Flower bud development of almond cultivars based on three different methods

“…This stage of anther development has been also reported in other Prunus species (Szalay, 2006;Fadón et al, 2018Fadón et al, , 2019. In apricot, many studies agree (Julian et al, 2009;Szalay and Németh, 2010;Andreini et al, 2012;Hajnal et al, 2013;Wu et al, 2019;Herrera et al, 2022) that the differentiation of archesporium tissues of flower buds has been related to the chilling fulfilment and with endodormancy release, an advanced microsporogenesis process was observed with the appearance of tetrads and pollen grain. The result of this work is in accordance with the reports of the authors.…”

“…Flower buds enter dormancy during the winter and resume their growth prior to flowering (Julian et al, 2009). Flower bud development slows down during endodormancy, during which period, there is no visible change and it accelerates again until is controlled by subsequent heat accumulation (Egea et al, 2003;Bartolini et al, 2006a;Hajnal et al, 2013;Sanchez-Perez et al, 2014;Szalay et al, 2019). In temperate climates, cultivars with fast flower bud development are highly exposed to the danger of frost.…”

“…Cultivars having fast flower bud development have short endodormancy period, therefore winter frosts can occur. Moreover, their blooming starts early and the flowers are more exposed to spring frost (Szalay and Németh, 2010;Hajnal et al, 2013). Early flowering almonds are a good choice for growing in warm areas where there are problems of insufficient chilling (Prudencio et al, 2018).…”

“…Flower bud development can be carefully studied during the dormancy period by microsporogenesis methods. The microsporogenesis development of apricot flower buds was studied during winter (Szalay, 2006;Szalay and Németh, 2010;Németh, 2012;Hajnal et al, 2013;Szalay et al, 2019). Six stages of microsporogenesis were identified and the time to each stage of development varied depending on genotypes.…”

“…Male meiosis was indicated as a possible biomarker to determine dormancy release and estimate apricot agroclimatic requirements. The relationship between dormancy and microsporogenesis in apricot flower buds was studied by Hajnal et al (2013); Julian et al (2009); Szalay et al (2019). The differentiation of archesporium tissues or beginning meiosis was indicated as a biomarker for dormancy release.…”