Staminate and pistillate flower maturity of 80 cultivars of young (<15 years old) pecan [Carya illinoinensis (Wangenh.) K. Koch] trees are presented. These patterns show that pollination and receptivity windows within the flowering season can be divided into very early, early, mid, late, and very late season protandrous (Type I) and protogynous (Type II) types. This system therefore provides a seasonally based 30-class Type I and Type II alternative to the standard two-class Type I and Type II system, thus offering enhanced resolution of flowering intervals and an improved means of selecting cultivars to ensure cross-pollination of yard and orchard trees. Scott-Knott cluster analysis of budbreak, nut ripening date, and date of autumn leaf drop segregated cultivars into one of several categories.
If the inline PDF is not rendering correctly, you can download the PDF file here.