Abstract
Measurements were made on 25 production units (mother and daughter) chosen at random in commercial five-year old or older fields of Grand Nam and Valery bananas in Honduras and Panama. Average stem weights in the areas varied between 33 and 47 kg. Grand Nain mother plants had 20% less leaf area than Valery (17.7 versus 22.4 m2). The ground area covered by extended leaves was 35% less with Grand Nain than Valery at shooting. At a population density of 1730 production units ha-1 the leaf area index was 3.21 for Grand Nain and 4.33 for Valery Leaf Grand index (length was 78 cm divided by width) of leaf No. 6 on flowered plants was 2.42 for Grand Nain and 2.91 for Valery. Grand Nain was 78 cm shorter than Valery in Honduras and 93-98cm shorter in Panama. The shorter height results in less wind losses and higher yields than in Valery. Gran Nain must be planted at higher population densities to obtain the same leaf area index as Valery. This should further increase yield over Valery. A plant similar to Grand Nain is proposed as the ideotype of model for breeding new varieties. In addition, there should be resistance to black Sigatoka disease, nematode root rot and all races of fusarial wilt. Tetraploids with their extended, drooping and often fragile leaves are unlikely candidates for this ideotyoe. Emphasis should be given to triploid breeding