Phenological growth stages and growing degree days of peach [Prunus persica (L.) Batsch] in sub‐temperate climatic zone of North‐Western Himalayan region using BBCH scale

Abstract

In this study, the phenological stages of peach have been described for the first time according to the BBCH scale (Biologische Bundesanstalt, Bundessortenamt and Chemische Industrie) and Baggiolini codes for five cultivars (Pratap, Tropic Snow, Tropic Beauty, Redhaven and July Elberta) in sub-temperate region of India, which markedly differentiates vegetative and reproductive stages occurring in peach. The growing degree days (GDD) are the best indicators for monitoring the different phenological growth stages and were determined from dormancy breaking to fruit harvest when the cultivars reached maturity. Pratap, Tropic Snow and Tropic Beauty were identified as early-season maturing with 814 ± 5.10, 996 ± 8.13 and 1004 ± 8.72 GDD, respectively. While, Redhaven was mid-season cultivar with 1502 ± 16.17 GDD, and July Elberta was the late-season cultivar with 1894 ± 6.00 GDD.Mid-season cultivar Redhaven performed better in India's sub-temperate region, accounting for higher yield (54.87 kg per tree), fruit length: diameter (1.11), TSS (12.26%) and total sugars content (10.26%). The description presented in the paper will act as a tool to provide a consensual unified approach for standardisation of phenological stages in peach and also for various cultural inputs and timely planning of harvesting. Moreover, the BBCH scale will act as a tool to assess the impact of climate change on crop phenology and to evaluate the adaptation of particular peach cultivars to different conditions.

Predicting Floral Bud Progression for Three Peach Cultivars

“…To determine the full bloom stage or date, most of the methodologies in the literature are focused on the moment when the cultivar 50% of fully open flowers [12,15]. In this research, observations were made for each one of the floral buds, and the full bloom dates were recorded individually.…”

“…Calendar days have been a tool used to establish the progression among bud stages in species such as peaches, starting on 1 January as a reference [12]. The evaluation of the occurrence between stages, even when comparing different cultivars, exhibits variations relevant to activities such as irrigation, fertilization, and pollination.…”

“…For instance, a comparison among the peach cultivars 'Pratap', 'Tropic Snow', 'Tropic Beauty', 'Redhaven', and 'July Elberta', during the 2020-2021 season, under sub-temperate conditions, showed meaningful variation in the transition of the phenological stages to reach the complete fruit development. Thus, the five cultivars ranged from 32 to 58 days to reach bud burst, 34 to 60 days to reach the single floral bud visible, 35 to 61 days for sepals to open, 36 to 63 days for the beginning of flowering, and 39 to 72 and 41 to 78 days to reach full bloom and petal fall stages, respectively [12].…”

“…In sweet cherries, 4-6 weeks were necessary for the change between bud burst and full bloom stages [14]. After the full bloom stage, the petal fall stage will determine the flowering duration, which has been defined as the difference between the days of full bloom and petal fall [12].…”

“…Currently, some research continues to apply the combination of phenological growth stages (in a determined scale) and the GDD. GDD are considered the best indicator for monitoring the phenology during growth development from budbreak to harvest [12]. Also, technology has been applied to assess the progression of peach phenology in different cultivars.…”