LIBRO-CONGRESO-CITRUS

S06
The experiment was conducted at 6 weeks after full bloom using satsuma mandarin and tangelo. As an
evaluation method for the potential fruit abscission, the fruits with peduncle were detached from a tree
and incubated on 1% agar medium (detached). As a control, the fruits on a tree were treated ringing on the
peduncle to prevent the translocation of photo-assimilates to the fruit (on tree). The ratios of fruit abscission
(separation of fruit from disk) at 168 h after treatment in both “detached” and “on tree” were over 70% in
tangelo and were below 20% in satsuma mandarin. The time course of abscission pattern in “detached” was
similar to that in “on tree” in both species. The result indicates that the fruit detachment method is useful for
an evaluation of the potential fruit abscission in citrus.
The flowers of 7 citrus species were treated with non-pollinated and open-pollinated. These fruits were
detached and incubated on agar medium at 5 weeks after full bloom. The ratios of fruit abscission at 96 h
after detachment in both open-pollinated and non-pollinated were over 80% in ‘Ponkan’, navel orange and
Iyo, and were below 30% in satsuma mandarin, hyuga-natsu and pummelo, respectively. The non-pollinated
fruits of satsuma mandarin, hyuga-natsu, pummelo were seedless. The results indicate that the potential of
citrus fruit abscission is different in species and the both of the seeded and seedless fruit abscission potential
is lower in satsuma mandarin, hyuga-natsu and pummelo. It is suggested that these species would be useful
for seedless citrus breeding.
S06P03
Cross-pollination and control of seed formation in ‘Afourer’ mandarin
Gravina A. 1 , Gambetta G. 1 , Fasiolo C. 1 , Espino M. 2 , and Rivas F. 3
1 Facultad de Agronomía. Universidad de la República (UDELAR), Producción Vegetal, Uruguay; 2 URUDOR (URUDOR), Departamento
Técnico, Uruguay; and 3 Instituto Nacional de Investigación Agropecuaria (INIA), Programa Nacional de Cítricos, Uruguay. agravina@
fagro.edu.uy
‘Afourer’ mandarin, a self-incompatible variety, produce under Uruguayan conditions high number of seeded
fruits. In order to reduce seed presence, four field experiments were performed, including plant net coverage
(exp. 1 and 2), and application of different concentrations of copper sulphate and gibberellic acid, one, two
or three times during the flowering period (exp. 3 and 4). Additionally, artificial pollinations were performed
with ‘Valencia’ orange and ‘Clemenules’ clementine pollens. Net covered trees had 99% of seedless fruit. In
experiment one, in two year-old plants, no differences in yield components between open pollination and
covered plants was registered, but in experiment two, with seven year-old trees, a significant fruit number
reduction on covered trees was verified. The most efficient treatments to diminish seeds was three applications
of GA 3 (50 mg L -1 ) alone or combined with CuSO 4 (25 mg L -1 ), that increased seedless fruit from 19 to 31%
(exp. 3) and from 26% to 52% (exp.4). Additionally, the average number of seeds per fruit decreased from 3.7
and 2.9 in the controls to 2.3 and 1.8, in experiment three and four respectively. Single flowers self pollinated
or artificially pollinated with ‘Afourer’ pollen, set similar seedless fruit number. ‘Afourer’ flowers pollinated
with ‘Valencia’ had the highest percentage of seeded fruit (88%) and seeds per fruit (3), while pollinated with
‘Clemenules’ clementine only 21% of the fruits had seeds.
S06P04
Changes of nutrient element contents and accumulation in fruit of navel orange during fruit
growth and development
Peng L.Z., Fa X., Cailun J., Li C., and Lili L.
Citrus Research Institute of Chinese Academy of Agricultural Sciences,Chongqing (CRICCAAS,CQ), China. penglz809@163.com
The changes of nutrient element contents and accumulation of N, P, K, Ca, Mg, S, Mn, Zn, Cu, Fe and B in
fruit of 30 years old ‘Seike’ navel orange (Citrus sinensis) on trifoliate orange (Poncirus trifoliata) rootstock
were studied. Results showed that: (1) During the fruit development, N, P, Mg, S, Mn and Zn contents in
fruit reached the highest levels in April, the highest K and Fe contents in July and the highest Ca content
in October. However B and Cu contents in fruit showed only small changes from April to November.
With the fruit growing and developing, N, P, K, Mg, S, Zn and B contents in fruit decreased to or near the
98 - VALENCIA CONFERENCE CENTER, 18th-23rd NOVEMBER 2012