Crop Load Management for Consistent Production of Honeycrisp Apples
The popularity and high fruit prices of the Honeycrisp apple in the market are largely due to the unique eating experience from this apple. Most consumers of Honeycrisp are impressed with the flavor, crispness and juiciness, which Honeycrisp delivers when it is grown properly. However, the biennial bearing tendency of this variety leads the tree to produce very large crops followed by very low crops. Fruit quality is not optimal with either high or low crop loads. We have previously reported on the effect of increasing crop load on tree growth, fruit size, fruit color, storage disorders and return bloom (Robinson and Watkins, 2003).
Our previous research has shown that the crop load carried by Honeycrisp trees had a large effect on tree vegetative growth in the 3rd-5th years. As crop load on Honeycrisp trees increased tree growth declined rapidly. In many Honeycrisp orchards excessive crop loads in the early years stopped tree growth preventing young orchards from filling the space allocated to each tree. To ensure proper tree growth we recommend that during the developmen- tal years of the orchard crop load of Honeycrisp be limited to no more than 4 fruits/cm2 TCA to allow the trees to fill their space (Robinson, 2008).
Our previous research has also shown that fruit size was re- duced by increasing crop load in a curvilinear relationship. Fruit size was reduced rapidly as crop load increased from 0 to about 7 fruits/cm2 of TCA. At a crop load of 7 fruits/cm2 TCA, fruit size was about 175 g (100 count fruit size). Fruit size was 150 g at crop loads of 10 fruits/cm2 or greater. This size is not commercially acceptable for Honeycrisp, which is sold as a premium apple,. In contrast, at very low crop loads, fruit size often approached 300 g, which is considered excessively large by most marketers. In today’s market a Honeycrisp fruit size between 200-220g is considered optimal. To obtain that fruit size in our studies would have required a crop oad of 5-6 fruits/cm2 of TCA.