FRUIT CHARACTERIZATION AND PROPAGATION OF HYBRID CITRUS ROOTSTOCKS IN PROTECTED ENVIRONMENT

The diversification of citrus rootstocks in Brazil is important in order to adjust to the diversification of abiotic and biotic stresses the trees are confronted, besides the need for horticultural traits of interest as dwarfism and high production efficiency and fruit quality. The performance of the genotype during the propagation stage is also relevant for rootstock selection. Therefore, fruits of hybrid rootstocks obtained or selected by Embrapa Citrus Breeding Program and commercial varieties were characterized and their propagation evaluated in a protected environment. The hybrids were ‘Indio’, ‘Riverside’ and ‘San Diego’ citrandarins, the hybrids HTR-051, TSKC x (LCR x TR)-040 and 059, LVK x LCR-010 and 038, TSKC x CTTR-002, TSKC x CTSW-041 and LCR x TR-001, and the commercial varieties ‘Swingle 4475’ citrumelo, ‘Flying Dragon’ trifoliate, ‘Rangpur’ lime selection Santa Cruz, and ‘Sunki’ mandarin selection Tropical. Collected data included biometric and physiological variables and technical coefficients. The experimental design was randomized blocks with four replications with 50 plants in the unit or 20 fruits per genotype, according to the evaluation procedure. ‘Swingle’ citrumelo and LVK x LCR-010 presented high seed production per fruit (23 to 26), while HTR-051 and LCR x TR-001 produced the least amounts (2 to 3). Polyembryony varied from 97,5% to 100% for TSKC x CTTR-002, TSKC x (LCR x TR)–040, LCR x TR-001, ‘Indio’, ‘Riverside’ and ‘San Diego’ citrandarins and ‘Sunki Tropical’ mandarin, and from 40% to 50% for ‘Flying Dragon’ trifoliate and LVK x LCR-010. Emergence of ‘Riverside’ citrandarin was faster (27 days) and more uniform in relation to the other genotypes (29 to 43 days). ‘Riverside’ citrandarin, TSKC x (LCR x TR)-059, ‘Sunki Tropical’ mandarin, ‘Swingle’ citrumelo and ‘Rangpur’ lime and its hybrids had the highest canopy and root system vegetative growth. All evaluated hybrid citrus genotypes could potentially be used as rootstocks.

Citrus spp.; breeding; hybrids of Poncirus trifoliata; polyembryony