AGRONOMIC PERFORMANCE OF THIRTY TWO CLONES OF 'PERA' SWEET ORANGE IN SÃO PAULO STATE, BRAZIL

Abstract

‘Pera’ sweet orange, one of the most important Brazilian sweet orange varieties, is high susceptible to Citrus tristeza virus (CTV), causing reduced yield and fruit quality. The ‘IAC’ clone, pre-immunized with a mild protective CTV isolate (‘PIAC’), is the most cultivated clone, but several other clones derived from spontaneous mutations have been selected. The agronomic performance of 32 clones was evaluated in seven experiments carried out in four regions of the SA£o Paulo state: Northern, Central, Southern and South, between which there is a temperature gradient. The results obtained is this study represent an important information about the behavior of several ‘Pera’ sweet orange clones in different soil and climatic regions of the SA£o Paulo state, also taking in consideration the presence of the original isolate or the ‘PIAC’ protective isolate. Genetic differences among clones were observed in relation to plant size, yield, productive efficiency and susceptibility to CTV. ‘OlA­mpia’, ‘IpiguAi’, ‘IAC’, ‘Bianchi’, ‘EEL’ and ‘IAC 2000’ clones showed good agronomic performance. However, ‘IAC 2000’ clone was highlighted with highest average production per plant, but with highly vigorous plants. Moreover, ‘OlA­mpia’ and ‘IpiguAi’ clones produced plants with a small size, but always with a high productive efficiency. The ‘IAC’, ‘Bianchi’ and ‘EEL’ clones produce plants with medium vigor and good productive efficiency.