Articles
CROP LOAD AFFECTS ‘HONEYCRISP’ FRUIT QUALITY MORE THAN NITROGEN, POTASSIUM, OR IRRIGATION
Article number
940_76
Pages
529 – 537
Language
English
Abstract
Two field studies were planted in 2002 using Honeycrisp apple trees on M.9 rootstock.
The first experiment compared four crop loads (0, 4, 8, 12 fruits/cm2 TCA), soil applied nitrogen (0 and 100 kg Nha-1), potassium (0 and 200 kg K2Oha-1) and irrigation (none and trickle irrigation) from 2002-2006. The second study compared foliar fertilizer treatments of N, B, Zn, Mg and Ca.
Crop load had a negative effect on shoot and tree growth, fruit size, firmness, soluble solids and dry matter concentration.
When crop load was high, fruits failed to develop characteristic flavor and color.
Increasing crop load reduced storage disorders (especially bitter pit), fruit rots and percentage of bad fruits.
Total crop value increased with increasing crop load up to 8-10 fruitscm-2 TCA. Nitrogen soil fertilization increased fruit size, yield, soluble solids and rot incidence but resulted in reduced red color, firmness and total crop value in two years.
Potassium fertilization increased fruit size, red color and total crop value but reduced fruit dry matter concentration.
Irrigation increased shoot and tree growth, yield and fruit size but reduced fruit soluble solids and increased crop value in only 1 year.
Annual water supply (rainfall and irrigation) was positively correlated with fruit red color, size, incidence of soggy breakdown and incidence of soft scald while fruit firmness, soluble solids, bitter pit incidence and rot incidence were negatively related to water supply.
Bitter pit incidence was most influenced by water supply during the early season near petal fall.
Foliar nutrient sprays had little effect on tree growth, yield or fruit quality.
Ca sprays reduced bitter pit incidence in only 1 year.
Fruit Ca concentration was not related to bitter pit incidence but fruit P concentration was positively related to bitter pit.
We also found a positive relationship between fruit P:S ratio and fruit red color.
The first experiment compared four crop loads (0, 4, 8, 12 fruits/cm2 TCA), soil applied nitrogen (0 and 100 kg Nha-1), potassium (0 and 200 kg K2Oha-1) and irrigation (none and trickle irrigation) from 2002-2006. The second study compared foliar fertilizer treatments of N, B, Zn, Mg and Ca.
Crop load had a negative effect on shoot and tree growth, fruit size, firmness, soluble solids and dry matter concentration.
When crop load was high, fruits failed to develop characteristic flavor and color.
Increasing crop load reduced storage disorders (especially bitter pit), fruit rots and percentage of bad fruits.
Total crop value increased with increasing crop load up to 8-10 fruitscm-2 TCA. Nitrogen soil fertilization increased fruit size, yield, soluble solids and rot incidence but resulted in reduced red color, firmness and total crop value in two years.
Potassium fertilization increased fruit size, red color and total crop value but reduced fruit dry matter concentration.
Irrigation increased shoot and tree growth, yield and fruit size but reduced fruit soluble solids and increased crop value in only 1 year.
Annual water supply (rainfall and irrigation) was positively correlated with fruit red color, size, incidence of soggy breakdown and incidence of soft scald while fruit firmness, soluble solids, bitter pit incidence and rot incidence were negatively related to water supply.
Bitter pit incidence was most influenced by water supply during the early season near petal fall.
Foliar nutrient sprays had little effect on tree growth, yield or fruit quality.
Ca sprays reduced bitter pit incidence in only 1 year.
Fruit Ca concentration was not related to bitter pit incidence but fruit P concentration was positively related to bitter pit.
We also found a positive relationship between fruit P:S ratio and fruit red color.
Authors
T. Robinson, S. Lopez
Keywords
Malus × domestica, crop load, nitrogen, potassium, calcium, bitter pit, senescent breakdown, soggy breakdown, irrigation
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