F&N-1 avocado cultivars

Many people have a favorite avocado, perhaps the one that grew in their backyard when they were growing up. What makes one person consider an avo­ cado “good” may be largely a matter of personal taste. But when horticulturists choose among seedlings and select one for plant propagators to increase and farmers to cultivate, many factors are involved. This publica­ tion is about the factors considered when selecting avo­ cado cultivars. Avocado (Persea americana) cultivars are selected and named because of particularly desirable fruit and tree characteristics. Every avocado tree grown from seed is a potential candidate for selection as a cultivar, be­ cause cross-pollination in avocado’s reproduction pro­ cess ensures genetic variability. Once selected, cultivars are propagated by vegetative methods, such as grafting, to produce genetically identical trees. The following sections describe characteristics con­ sidered in evaluating avocados and some of the factors affecting the expression of those characteristics. This in­ formation may help home gardeners and commercial growers to distinguish and select for desirable character­ istics in avocodo cultivars for their situations. At least, it can provide the reader with increased knowledge of hor­ ticultural evaluation methods and greater appreciation of the genetic diversity present in avocado. The expression of an avocado cultivar’s genetic char­ acters varies with environmental influences associated with climate and seasonal variation in temperature, rela­ tive humidity, and rainfall. Avocado characters affected by climate include disease resistance, yield, bearing habit, fruit size and quality, and season of maturity. Therefore, a cultivar that is productive or has good fruit elsewhere in the world may not be adapted to growing in Hawaii, and one that does well in Hawaii at 1500 ft elevation may do poorly at 100 ft. Hawaii has many different soil types and micro-cli­ mates, and these may change over short distances. For this reason, it is difficult to recommend “the best” avo­ cado cultivars for specific locations unless experience is available for that (or a very similar) location. Lacking prior experience, an experimental approach is called for in selecting an avocado cultivar that is well adapted for a given location.