MORPHOLOGIC CHARACTERIZATION OF GUAVA GERMPLASM FROM MÉXICO: IMPLICATIONS ABOUT ITS CONSERVATION AND BREEDING

ABSTRACT Guavas (Psidium guajava L.) growing throughout Mexico show broad morphologic and productive variation due the crop is commonly sexual-propagated. The characterization of genetic diversity of Mexican guava germplasm will allow identify potential parents for genetic improvement as well as the production of new clonal cultivars. In this work 88 guava accessions [87 belong to P. guajava and one from P. friedrichsthalianum (Berg.) Niedz] growing in Huanusco, Zacatecas Mexico were characterized on the basis of 50 morphologic descriptors. The 95% of germplasm shows ovoid or round fruit shape; 92% fruits with beige or white mesocarp and 87.5% has yellow fruits. Fruits with these traits are locally named as ‘China’ or ‘Media China’ and they are preferred for fresh use. Seven quantitative traits were those that better described the morphologic variability of germplasm: two from trees (stem thickness and leaf length) and five from fruits (polar and equatorial diameter; sepal size; calyx cavity diameter; and total solid soluble content). Three accessions (numbers 68, 52, and 49) outstand due their high values of tree growth under field conditions although showing small fruit sizes while other five accessions (numbers 79, 57, 60, 78, and 56) exhibited small tree sizes but high values for fruit, sepals and calyx cavity, and total solid soluble contents.