Effect of AVG (Retain®) on yield and twin seeds incidence of almond trees, and orchard profit under different conditions of fruit set and PAR interception
Low yield (kg ha‑1) is the main weakness of almond orchards in Chile (under 2,000 vs. 2,500 kg ha‑1 in California or Australia) mainly due to weather conditions that would affect pollination and fruit set.
With the aim of improving fruitlet retention and fruit set, a study assessing the effect of the ethylene biosynthesis inhibitor AVG (Retain®) in Nonpareil and Carmel almond trees was carried out for 3 seasons, with a total of 4 trials per cultivar.
The results of all the experiments were integrated and the profit of the treatment was simulated under different scenarios, according to fruit density and orchard PAR interception.
To normalize tree size, the fraction of PARi (photosynthetically active radiation intercepted) was measured with a ceptometer and expressed as m2 of intercepted PAR (fraction multiplied by allocated space). Different concentrations (63 to 125 mg L‑1) and timings between bloom (65 to 69 BBCH phenological scale) and fruit drop (FD; 73 BBCH phenological scale) were evaluated.
The results obtained concluded that: both in Nonpareil and in Carmel, the AVG sprayed between full bloom (FB) and petal fall (PF) (65 to 69 BBCH phenological scale) significantly increased the double seed incidence; sprays on jacket fall (JF; 71 BBCH) and early fruit drop (IFD;72 BBCH phenological scale), being the latter more effective, significantly increased the fruits m‑2 PARi at harvest and, consequently, the yield, without affecting average seed weight.
The double spray with 63 mg L‑1 in JF and IFD was instead not effective on fruit retention, and the double application of 125 mg L‑1 did not show better response than a single application in JF or IFD. Finally, the spray of 125 mg L‑1 AVG (Retain®) generates a sufficient yield increase to make the application profitable, even under conditions of low fruit density (250 fruits m‑2 PARi or 0.25 kg m‑2 PARi) in orchards intercepting 60% PAR.
Beyá-Marshall, V. and Reginato, G. (2022). Effect of AVG (Retain®) on yield and twin seeds incidence of almond trees, and orchard profit under different conditions of fruit set and PAR interception. Acta Hortic. 1344, 37-44
DOI: 10.17660/ActaHortic.2022.1344.7
https://doi.org/10.17660/ActaHortic.2022.1344.7
DOI: 10.17660/ActaHortic.2022.1344.7
https://doi.org/10.17660/ActaHortic.2022.1344.7
Prunus dulcis, aminoethoxyivinylglicine, crop value, fruit set
English