SCS427 Elenise: late-ripening apple variety of good storability and resistance to Glomerella Leaf Spot

‘SCS427 Elenise’ (parents: Imperatriz and Cripps Pink) was released for being an apple variety resistant to Glomerella Leaf Spot, for producing red apple with late maturation, with high conservation capacity and pulp texture equivalent to the fruit Cripps Pink’s parent, but with less acidic flavor. It represents the opportunity to extend the harvest window and offer the market high quality apples throughout the inter-harvest period.


Introduction
The availability of commercial apple varieties of adequate fruit quality to attend the expectations of Brazilian market is restricted in Brazil (KVITSCHAL et al., 2019). Currently, up to 94% of the Brazilian apple production comes from the varieties Gala and Fuji and their colored sport mutations (FACHINELLO et al., 2011). It makes fruit handle a more challenging practice due to the high demand for labor and apparatus for harvesting, transportation and storage room loading in a short period. However, in most microclimates, where apples are grown in southern Brazil, the winters are shorter and growing seasons are longer than those in most traditional temperate-zone apple producing countries. So, there are fewer chilling hours' accumulation, limiting the cultivation of apple varieties with high chilling requirement. On the other hand, it is possible to extend the apple-harvesting season in subtropical climate regions. So, it is possible to offer varieties that attend to a wide spectrum of fruit ripening, with picking time from one month before Gala apples by using varieties of local low chilling requirement to at least one month after the ripening of late apples like Fuji (SEZERINO et al., 2018).
Gala traditional sport mutations are very susceptible to the most important pathogens present in apple orchards of southern Brazil, including Glomerella Leaf Spot (Colletotrichum spp.) (FURLAN et al., 2010), whose severity has enlarged in the last years, increasing production costs per unit. The breeding for new varieties resistant to diseases is the cheapest and the most efficient alternative to prevent pathogen damages and has been the goal of apple breeding programs worldwide in the last decades (SANSAVINI et al., 2004).
The research on apple breeding at Epagri has aimed at the development of new varieties better adapted to the local climate and with a better spectrum of resistance to the main local diseases (DENARDI et al., 2019). Also, enlarging the picking time by offering new apple varieties of fruit ripening later than Fuji's ripening can be an effective opportunity to extend the current 2.5 months of Gala and Fuji harvest period to, at least, 4.5 months. However, these late fruit ripening varieties must have long fruit storability, in order to offer high quality apple fruits in terms of flavor and flesh texture to the consumers over the offseason. In this sense, the Epagri's Apple Breeding Program developed the new apple variety SCS427 Elenise that adds many of these characteristics, and with high resistance to Glomerella Leaf Spot. Its fruits ripe later in the season as the 'Cripps Pink' parent, have red skin color, excellent flavor, flesh texture and very good fruit storability. Fruit of SCS427 Elenise has high sugar and acid content which enhance its flavor. 'Cripps Pink' fruit is also recognized by the outstanding flavor, although it can be rated as too acid to most of Brazilian apple consumers, especially at harvest season moment.

Origin and breeding methodology
The cross that originated 'SCS427 Elenise' was made at Epagri in 2001 and involved the varieties Imperatriz (♀) and Cripps Pink (♂), as presented in Figure 1. The main objective of this cross was to join the low to moderate chilling requirement, good adaptation to the mild winters of Midwestern region of Santa Catarina state and resistance to Glomerella Leaf Spot (Colletotrichum gloesporioides) from the 'Imperatriz' parent to the high fruit quality based on flavor, skin-color and storability from the another parent, 'Cripps Pink'. The artificial hybridization, collecting and germination of the seeds, and the initial cultivation of the seedling populations in the nursery were as previously described by Denardi et al. (2013). The preliminary evaluations for diseases resistance, precocity of fruiting, as well as the advanced evaluation for local climatic adaptation and fruit quality on dwarfing rootstock also followed the methodology described by these authors. The evaluations for Glomerella Leaf Spot resistance were performed through artificial inoculation, as described by Furlan et al. (2010).
The segregating population was constituted by 602 seedlings, 232 of which were chosen to be grafted on M.9 rootstock (one tree per pre-selection) aiming to evaluate agronomic traits and fruit quality on orchard located at Epagri/Caçador Experimental Station. The most promising selections were grafted on the rootstock G.814 subsequently and carried out on trials for advanced studies at Epagri, Caçador Experimental Station and at Fischer S/A Agribusiness Company, in Fraiburgo, at the Midwestern of Santa Catarina. These studies were performed under an experimental randomized block design of four replicates with four trees per plot, at a spacing of 1.5 m between plants and 4.0 m between rows (1,666 trees per hectare), including Galaxy and Fuji Suprema varieties that were used as controls. At this stage, it was evaluated the tree vigor, the bud break potential in local climatic conditions, the phenology of flowering and fruit ripening, the yield (kg per tree) and the fruit weight (g), according to the methodology described by Denardi et al. (2013). About post-harvest studies, apple fruits of 'SCS427 Elenise' and 'Cripps Pink' were harvested 218 and 215 days after full bloom, respectively, and assessed for maturity and quality at the harvest (day zero) and after storage, as described in Argenta et al. (2013) and Argenta et al. (2018). All fruits were cooled at 1°C in 36 h after harvest and stored in controlled atmosphere conditions -CA (1.5 kPa O 2 , < 0.5 kPa CO 2 ) at 0.7°C.

Description, perspectives and shortcomings
Based on trunk cross sectional area (TCSA), 'SCS427 Elenise' is similar to 'Galaxy' regarding to the vigor, but less vigorous than 'Fuji Suprema' (Table 1). Its growing habit is quite similar to the 'Cripps Pink' variety, with tendency to upright branches, requiring a good management of the trees. The chilling requirement of 'SCS427 Elenise' is moderate, indicating a slightly better bud-break potential score to local climate in comparison to 'Galaxy' and 'Fuji Suprema'. Nevertheless, it is necessary to use chemicals to induce bud-break after dormancy of 'SCS427 Elenise' in this region. The blooming period of 'SCS427 Elenise' has full coincidence with that of 'Galaxy' and a few days later than that of 'Fuji Suprema'. 'SCS427 Elenise' is similar to 'Galaxy' on precocity of fruiting, but more precocious than 'Fuji Suprema' based on the intensity of blooming and fruiting on one-year-old branches of young trees (data not shown). This has a positive effect on the payoff of initial costs for orchard planting and on the cumulative yield of the orchards. 'SCS427 Elenise' presents a great ability to differentiate flowering buds on brindles, even showing upright growing habit that requires correct canopy managing in order to maintain good equilibrium between the vegetative and the reproductive development. When cultivated on the rootstock G.814 in the Midwestern of Santa Catarina, 'SCS427 Elenise' showed yield similar to 'Galaxy' and 'Fuji Suprema' (Table 1) along four crop seasons and for cumulative yield (from 2011/12 to 2014/15), so it has a good yield potential for Brazilian conditions. However, it is very important a good management of thinning because it has been observed some biennial bearing in some orchards with 'SCS427 Elenise'.
According to artificial disease inoculation tests, 'SCS427 Elenise' showed high resistance to Glomerella Leaf Spot (Colletotrichum gloesporioides), being this trait one of the main advantages of this variety for growing in Brazil, where this disease is very aggressive and damaging on    a good choice for growers to extend the period for harvesting apples in Brazil. The fruit skin color is mid-dark red-pink over a green-yellowish background on a bicolor standard, resembling 'Cripps Pink' parent. The fruit shape is globose to cylindrical and the size is larger than 'Galaxy' and 'Fuji Suprema' (Table 1). The fruit flesh is cream white, firm, crispy and very juicy. The flavor is sweetsub-acid, being less acid than 'Cripps Pink' along the first four months after harvest, getting well-balanced flavor after this period in CA cold storage. According to post-harvest trials data (Figure 2), the starch degradation indexes (1-9 scale) of 'SCS427 Elenise' (4.5±1.1) and 'Cripps Pink' (3.5±1.2) apple fruits are not different when both were harvested at the same day, indicating they were quite similar in maturity stage. The soluble solid content (SSC) in 'SCS427 Elenise' fruits was higher at harvest and remained more constant than its 'Cripps Pink' parent along 8 months in CA cold storage. However, 'SCS427 Elenise' showed higher flesh firmness and lower titratable acidity than 'Cripps Pink' at the harvest date. The differences on flesh firmness at the harvest increased throughout the storage period. While the flesh firmness remained unchanged in 'SCS427 Elenise' (~18 lb), it has decreased significantly on 'Cripps Pink' along the 8 months in CA cold storage. The rates of sugar increased and acidity decreased in the apples evaluated along the 8 months of storage, being higher in 'Crisp Pink' than in 'SCS427 Elenise'. Therefore, the differences regarding SSC/TA ratio gradually showed the tendency of reducing from harvest to the 6 th month of storage and disappeared after this time of storage. 'SCS427 Elenise' fruits did not develop symptoms of physiological disorders CO 2 (data not shown) and superficial scald during the 8 months, while 'Cripps Pink' showed an increase in superficial scald symptoms along this period in CA cold storage. However, the development of fungal rots along CA cold storage was susceptible varieties (ARAÚJO et al., 2016). It is moderate resistant to Apple Scab (Venturia inaequalis), although it is not immune. 'SCS427 Elenise' is tolerant to Powdery Mildew (Podosphaera leucotricha), but it is susceptible to Bitter Rot (Glomerella cingulata).
The fruit ripening on the trees begins approximately at the same time of 'Cripps Pink': late April at Midwestern of Santa Catarina, Brazil. The fruits picking is another big goal of this variety, because the apples harvesting window in Brazil usually finishes with the 'Fuji' clones harvest, although the Brazilian climate allows picking apples until late April and early May. Therefore, the variety SCS427 Elenise is slightly higher on 'SCS427 Elenise' than on 'Cripps Pink' fruits. In general, 'SCS427 Elenise' fruits present potential storage superior to 'Cripps Pink', by better firmness conservation and less susceptibility to the physiological disorders related to superficial scald and CO 2 damage, and their storage potential in CA seems to be greater than 8 months.
'SCS427 Elenise' apples show a slow flesh and juice browning because of the low oxidative reaction of their compounds (PRESTES, 2019). Therefore, in addition to the high potential for fresh fruit market, the variety SCS427 Elenise can promote changes on industries of apples minimally processed and apple juice in Brazil, whose depends on 'Gala' and 'Fuji' fruits nowadays.

Availability of vegetative material for propagation
The variety 'SCS427 Elenise' is under Plant Varieties Rights Application at SNPC/MAPA (Serviço Nacional de Proteção de Cultivares/Ministério da Agricultura, Pecuária e Abastecimento, Brazil). In order to get young trees, growers may contact the Epagri's licensees or Caçador Experimental Station at 55 (49) 35616800.