O. S. Passos

Poliembrionia e atributos morfológicos de sementes de porta-enxertos de citros

Seed polyembryony is an important trait for breeding and commercial multiplication of citrus rootstocks. This study evaluated relationships of polyembryony with different morphological seed traits of 12 citrus genotypes selected as rootstocks. The following traits were evaluated individually on 50 seeds per genotype: seed mass, height, width and embryo number, polyembryony level, difficulty for seed coat extraction, and seed color, which was estimated by a two-grade scale representing predominant colors on the endosperm. Data was submitted to variance analyses and the means were compared by the Scott-Knott Test (P < 0.05). Pearsons Correlation Coefficients were determined among all variables for all genotypes and individually. Citrus rootstocks had significantly distinct seed traits and could be classified in three polyembryony groups, with three Rangpur lime selections presenting polyembryony lower than 50% and the citrandarins as totally polyembryonic. Other trifoliate hybrids showed low to intermediate polyembryony. Seed coat extraction was more difficult in smaller seeds. For majority of genotypes, the number of embryos in the seed had positive correlation to the seed mass, height and width and negative correlation to the color ratio, which was calculated by the division of the lowest and highest color grades. This result suggests that the whole seed color analysis may be an alternative method for a rapid visual evaluation of polyembryony manifestation.

PERFORMANCE OF ‘TUXPAN VALENCIA’ SWEET ORANGE GRAFTED ONTO 14 ROOTSTOCKS IN NORTHERN BAHIA, BRAZIL

In the State of Bahia, Brazil, the citrus industry is located on the north coast with the prevalence of the combination ‘Pera’ sweet orange on ‘Rangpur’ lime. Scion-rootstock diversification may contribute to the increase of yield and the extension of harvest season, as long as to decrease the risk associated to abiotic and biotic stresses. Therefore, the performance of ‘Tuxpan Valencia’ sweet orange grafted onto 14 rootstocks was evaluated in Rio Real – BA. Planting was performed in 2006 under rainfed cultivation on cohesive ultisol and tree spacing of 6.0 m x 4.0 m. Tree size, yield and fruit quality were evaluated in the period of 2010-2014, in addition to tree survival at nine years old and drought tolerance in the field based on leaf wilting. In the evaluated conditions, ‘Sunki Tropical’ and ‘Sunki Maravilha’ mandarins led to the highest scion canopy volume. The highest accumulated yield in five harvests was recorded on ‘Santa Cruz Rangpur’ lime, ‘Volkamer’ lemon, ‘Riverside’ and ‘Indio’ citrandarins, ‘Sunki Tropical’ mandarin and the hybrid TSKC x (LCR x TR) – 001. ‘Riverside’ and TSKFL x CTSW – 049 induced higher yield efficiency on the canopy. The rootstocks did not influence the tree survival nine years after planting except for lower survival of TSKFL x CTSW – 049. Drought tolerance was not affected either. Regarding to the fruit quality of ‘Tuxpan Valencia’, the rootstocks influenced the juice content, soluble solids and technological index with the citrandarins, ‘Santa Cruz Rangpur’ lime, ‘Volkamer’ lemon and ‘Sunki Tropical’ mandarin presenting higher performance in general.

Initial horticultural performance of nine ‘Persian’ lime selections grafted onto Swingle citrumelo

‘Persian’ lime (PL) [Citrus latifolia (Yu. Tanaka) Tanaka] is an important species both for domestic fresh fruit consumption in Brazil as well as the export market, since the country is one of the largest producers in the world despite the fact that, in commercial plantations, it is still not uncommon to find trees with low productivity and high plant vigor of unknown origin. Selections of Persian lime ‘CNPMF–2000’, ‘CNPMF–2001’, ‘CNPMF–01’, ‘CNPMF–02’, ‘IAC–5’, ‘IAC–5.1’, ‘Bearss’, ‘Persian–58’, and ‘5059’, were therefore grafted onto Swingle citrumelo [C. paradisi Macfad. cv. Duncan × Poncirus trifoliata (L.) Raf.] rootstocks and evaluated in Cruz das Almas, Bahia, Brazil in a field experiment conducted in a completely randomized block design with five replications and two trees per plot. The biometric attributes (canopy height, diameter and volume), yield parameters (yield during the off-season harvest period, yield per plant, production efficiency), and fruit quality traits, were evaluated. The ‘CNPMF–2001’, ‘CNPMF–01’, ‘CNPMF–02’, ‘IAC–5’, and ‘Bearss’ selections had 5-11 % shorter trees than the other cultivars. ‘CNPMF–01’, ‘CNPMF–02’, ‘Persian–58’, and ‘5059’ presented higher yield efficiency values, between 3.1-3.4 kg m−3, and higher yield levels during the off-season harvest periods. The ‘Bearss’, ‘Persian–58’, ‘CNPMF–2000’, ‘IAC–5.1’ and ‘5059’ selections had more acid fruits and the latter three, smaller fruits. Based on their horticultural performance up to eight years of age, ‘CNPMF–01’, ‘CNPMF–02’, ‘Persian–58’ and ‘5059’ selections were the most promising varieties of Persian lime.

Initial performance of alternative citrus scion and rootstock combinations on the northern coast of the state of Bahia, Brazil

1Agronomist, Master of Science in Agrarian Sciences, Federal University of Recôncavo da Bahia, Cruz das Almas-BA. Emails: m.s.amorim@hotmail.com, natianafranca@yahoo.com.br. Master’s work of the first author with CAPES scholarship. 2Agronomist, researcher at Embrapa Cassava & Fruits, Cruz das Almas-BA. Emails: eduardo.girardi@embrapa.br; abelmon.gesteira@embrapa.br, walter. soares@embrapa.br, orlando.passos@embrapa.br Abstract The diversification of scion and rootstock varieties is tremendously necessary for the citrus industry in Northeastern Brazil. The initial performance of 13 sweet orange varieties grafted onto ‘San Diego’ citrandarin, and of ‘Cara-Cara’ navel orange and ‘CNPMF-02 Persian’ lime grafted onto several rootstocks was evaluated in the municipality of Inhambupe, northern coast of the state of Bahia. Three trials were carried out separately, and tree size, fruit production and quality were assessed in the first three crops, with planting in 2008 at 6.0 m x 3.0 m spacing with supplemental irrigation. ‘Aquiri’, ‘Biondo’, ‘Agridoce’, ‘Kona’, ‘Pineapple’, ‘Russas CNPMF-03’ and ‘Salustiana’ sweet oranges showed the largest cumulative production in the first three crops. ‘Pera CNPMF D-6’, ‘Westin CNPMF’ and ‘Salustiana’ sweet oranges had fewer seeds per fruit, being more appropriate for fresh fruit market, in addition to greater production efficiency for the first one. Although ‘Westin CNPMF’ has shown good fruit quality, its initial production was low. ‘Florida’ rough lemon and ‘Volkamer’ lemon induced higher cumulative production compared to ‘Cara Cara’ navel orange, but tree size and fruit quality were not influenced by any evaluated rootstock. ‘Cleopatra’ mandarin and ‘Riverside’ citrandarin led to higher tree size and cumulative production and heavier fruits of ‘CNPMF-02 Persian’ lime. All scion and rootstock combinations have potential for cultivation on the northern coast of the state of Bahia and appear as an alternative to the prevalent ‘Pera’ sweet orange on ‘Rangpur’ lime combination.

Plant growth, yield and fruit quality of ‘Piemonte’ tangor grafted onto 14 rootstocks on the northern coast of the state of Bahia, Brazil

1Agronomist, Master of Science in Agrarian Sciences, Federal University of Recôncavo da Bahia, Cruz das Almas-BA. E-mails: natianafranca@ yahoo.com.br, m.s.amorim@hotmail.com. Master’s work of the first author with CAPES scholarship. 2Agronomist, researcher at Embrapa Cassava & Fruits, Cruz das Almas-BA. Emails: eduardo.girardi@embrapa.br, abelmon.gesteira@embrapa. br, orlando.passos@embrapa.br, walter.soares@embrapa.br Abstract In the state of Bahia, Brazil, citrus production is mainly on the Northern Coast region, with major cultivation of ‘Pera’ sweet orange grafted onto ‘Rangpur’ lime. The production of mandarins and mandarin-like fruits is very low in spite of the increasing regional consumption. Varieties that are adapted to tropical sub humid conditions should be evaluated on different rootstocks for cultivation recommendation. This study assessed the performance of ‘Piemonte’ tangor over 14 rootstocks in Rio Real, BA. Planting was performed in 2006 on a cohesive yellow argisol, at 6.0 m x 4.0 m spacing and with no irrigation. Plant growth, production, and physicochemical attributes of fruits in 2010-2014 were assessed, in addition to tree survival and drought tolerance based on leafroll. At nine years of age, rootstocks that induced greater cumulative production of ‘Piemonte’ were ‘Riverside’ and ‘Indio’ citrandarins, ‘Santa Cruz Rangpur’ lime, and ‘Cleopatra’, ‘Sunki Tropical’ and ‘Sunki Maravilha’ mandarins. Although four hybrid rootstocks were semidwarfing, their mean efficiency was equivalent to the other rootstocks (≈ 5.5 kg m-3), resulting in the lowest production. Drought tolerance and tree survival were similar among rootstocks with minimal loss, except for TSKFL x CTSW 049 hybrid with only 33.33% of survival. ‘Piemonte’ tangor produced fruits with general good quality under the evaluated conditions, but only peel thickness and technological index (TI) were influenced by rootstocks, with the lowest TI averages recorded for fruits harvested from scions grafted onto TSKC x (LCR x TR) 001 and ‘Volkamer’ lemon.