This Is AuburnElectronic Theses and Dissertations

Determining a Maturity Index and the Effect of Chilling Requirments, and Cytokinin Applications on Three New Kiwi Cultivars




Wall, Clinton

Type of Degree





The kiwi industry in Alabama is small but has potential for strong growth. Alabama’s climate shares many similarities to several large production regions around the world, including China and New Zealand. But in order for production to be successful in Alabama a viable production system must be established. The goal of this research was to study two new cultivars of A. chinensis that originated from China, ‘Golden Sunshine’ and ‘Golden Dragon’, and one A. deliciosa cultivar, ‘AU Fitzgerald’, that was selected from a population of A. delicosa plants grown from seed planted in south Alabama. There were three main objectives that focused on production issues. The first concerned fruit quality and development of a maturity index for each cultivar to ensure proper harvest timing. Second, was to determine the chilling requirement of each cultivar to enable the selection of the proper areas in the state suitable for their production. The third was to determine the efficacy of cytokinin plant growth regulators for improving fruit size and quality. In a two year study with ‘AU Fitzgerald’, optimum maturity was reached 135-150 days from full bloom with a 6.5% soluble solids content (SSC) and having a firmness of 5.8-7.2 kg. It was found a single year study with the two A. chinensis cultivars that ‘Golden Dragon’ entered the climacteric 135 days from full bloom at 7 % SSC and a firmness of 6.75 kg was reached. ‘Golden Sunshine was entering the climacteric 95 days from full bloom at 6% SSC and a firmness of 7.2 kg. ‘Golden Dragon’ and ‘Golden Sunshine’ had the lowest chilling requirements for flowers at 800 and 900 h, respectively. Thus ‘Golden Dragon’ and ‘Golden Sunshine’ would be suitable for more southern regions where chilling hours received are typically below 1,000. ‘Golden Dragon’ is the earliest flowering cultivar, and ‘Golden Sunshine’ may show the most promise for major production because of its low chilling and fairly high heat unit requirement. ‘AU Fitzgerald’ had a chilling requirement of 1100 h and heat requirement of 13,750 growing degree hours (GDH) for optimum flower development,. Exogenous applications of cytokinin increased fruit fresh weight. There was an 18% increase in fresh weight for ‘AU Fitzgerald’ treated fruit. ‘Golden Dragon’ and ‘Golden Sunshine’ had an average increase in fresh weight of 14% and 27%, respectively for treated fruit. There was no significant difference in SSC (%) or dry matter (%) among the three cultivars. ‘Golden Sunshine’ had a slight decrease in firmness for treated fruit which appeared to reduce shelf life by about one week.