Contrasting effects of acid and nonacid pummelos on the acidity of hybrid citrus progenies

Abstract does not appear. First page follows.

Introduction

Reports on the levels of acid in hybrid progenies of fruit trees have been rather fragmentary. Most reports describe only the general behavior of progenies; when data on individual progenies are given, acid levels often cannot be separated from sugar levels or other factors of fruit quality. (Bishop (1951))4 and (Kimball (1930)), in crosses of several apple varieties with Northern Spy and Mclntosh, found that some parents gave a much higher percentage of acid individuals than did others. On the basis of organoleptic tests, (Klein (1958)) indicated that sweetness is recessive to acidity in apple progenies. Using chemical tests, (Nybom (1959)), whose report is more comprehensive than most others, concluded that sweetness is determined by a single recessive gene. In peach, (Connors (1922)) reported that Early Crawford transmitted acidity. (Blake (1937)) indicated association of blood-red flesh, astringency, and early ripening with acidity in progenies of the J. H. Hale peach with Dwarf Blood and Chinese Blood.

Although there are several reports (Harding and Fisher, 1945); (Harding and Sunday, 1949); (Harding and Wadley, 1945); (Harding, Winston, and Fisher, 1940); (Sinclair and Bartholomew, 1947) on the seasonal changes of acid levels in several varieties of citrus fruits in relation to their palatability, there seem to be no data concerning the behavior of acidity in progenies from parents of differing acid levels.

In the course of the citrus breeding program under way at the University of California Citrus Experiment Station, Eiverside, fruiting populations of hybrids involving the pummelo (Citrus grandis Osbeck) as one parent have been under examination for the last seven years. The pummelos possess certain