AFRODITE – new oat cultivar with nematode resistance

The oat cultivar IPR Afrodite, resulting from a cross between CFT 2 and the inbred line ER 88144-1, is high-yielding, has grain quality traits that are relevant for food processing and industry, and is resistant to the root-knot nematode species Meloidogyne incognita, M. javanica, M. paranaensis and M. enterolobii.


INTRODUCTION
In Brazil, oat is being cultivated for a number of purposes, for example, agricultural diversification, as well as grain production for the food industry.The increase in the number of derivatives from this species may be due the fact that oat can be a food source of iron, calcium, antioxidants, proteins, vitamins, carbohydrates, and soluble and insoluble fibers.In addition, it is considered a functional food, for preventing or contributing to treatments of diseases when consumed routinely, aside from the well-documented nutritional functions.
According to CONAB (2014, http://www.conab.br),an output of 358 thousand tons of oat grain was expected in 2014, from an approximate acreage of 143 thousand hectares, corresponding to a grain yield of 2493 kg ha -1 .The significant rise in total production shows the increasing relevance of this crop in Brazil.In relation to 1976, with a production of 37.4 thousand tons, the increase was 9.6 fold, based on the estimated production volume for 2014.
According to Barbosa Neto et al. (2000), until the early 1980s, oat cultivars (Avena sativa L.) from Uruguay and Argentina were used.These had adaptation problems, mainly in relation to late cycle and tall height, which stimulated breeding programs at institutions such as Universidade Federal do Rio Grande do Sul (UFRGS) and Universidade de Passo Fundo (UPF).Currently, research on oat breeding has been intensified in the South of Brazil, especially in many research institutions and universities of the States of Paraná and Rio Grande do Sul.
The Instituto Agronômico do Paraná-IAPAR initiated an oat breeding program with industrial focus, in 1999, by introductions of inbred lines for crosses, stimulated by other breeding programs of institutions such as UFRGS, UPF, Universidade Federal de Pelotas (UFPel), Universidade Tecnológica Federal do Paraná (UTFPR) and Fundação Agrária de Pesquisa Agropecuária (FAPA).
The objective of the IAPAR oat breeding program is the development of new oat cultivars with high yield, wide adaptability and stability, tolerance to biotic and abiotic stresses, aside from grain quality traits that meet the standards of the food processing industry.

BREEDING METHOD
The oat cultivar IPR Afrodite was developed from a single cross between cultivar CFT 2 (of the UTFPR breeding program) and the inbred line ER 88144-1 (FAPA breeding program), in the 2000 growing season, with the genealogy IP2000248-0L-0L-4G-3L-0L, i.e., the cross was number 248, in the chronological order of IAPAR oat crosses.Letter L indicates Londrina and G Ponta Grossa, both in the State of Paraná, where the crosses and selection processes were conducted.The numbers refers to the breeding method (0=bulk or mass selection, and 4G and 3L indicate the number of plants selected by the pedigree method) The modified pedigree method was used for breeding (Riede et al. 2001), by which panicles of the best F 2 plants were selected and threshed in bulk, forming the F 3 bulk.This generation was grown in Ponta Grossa, and four individual plants were selected to continue the process.In F 4 , three individual plants were selected in Londrina.In F 5 , the best of these selected plants, were sown on experimental plots (5.1 m 2 ), and harvested as superior line and labeled AL 0548.
AL 0548 was evaluated in Preliminary Grain Yield Tests and compared with three control cultivars.The Preliminary Tests -Year I were carried out in 2006, in Londrina and Ponta Grossa, and the Preliminary Tests -Year II in 2007, in Londrina, Ponta Grossa and Palotina.The grain processing quality was analyzed during three growing seasons in a food quality laboratory.
The performance of inbred line 0548 was superior in these evaluations, and it was chosen in 2008 for the Test of Regional Inbred Lines and in 2009 and 2010 for the Test of Brazilian Inbred Lines, to determine the Value for Cultivation and Use.These VCU tests provide data underlying the registration of new cultivars.Both tests were carried out in a cooperative effort of institutions of the Brazilian oat research committee (CBPA), mainly of the states RS, PR and SP.In this partnership model, each institution is responsible for tests at a certain number of locations (Table 1).
After three years of testing, the inbred line AL 0548 was assessed in an internal ranking of IAPAR and subsequently approved at the 31 st annual meeting of CBPA.The decision was taken to release IPR Afrodite as new oat grain cultivar and, thereafter, initiate the request of registration by the Ministry of Agriculture, Livestock and Food Supply (MAPA) in 2011.

PERFORMANCE
In the mean of the evaluations, the cultivar proved suitable for all producing regions in Brazil, with a medium cycle (85 days from emergence to silking and 124 days to maturation), intermediate plant height (114 cm), and moderate lodging resistance at a seeding rate of 300 to 350 viable seeds per square meter (Table 2).The panicles have awns, with semi-erect and equilateral branching, medium density and decumbent position.The mean hectoliter weight ranged from 45 to 48 kg hL -1 , with a mean of 46 kg hL -1 , and 1000-seed weight from 27 to 29 g, with a mean of 28 g.
In relation to the grain yield in the Preliminary Tests, at three locations in 2006 and 2007, and in 28 Regional VCU   3).
With regard to grain processing, the grains were classified as flint with good uniformity, light color and low presence of malformed grains.The percentage of grains retained in 2mm-sieves of cultivar IPR Afrodite was also over 85%.The threshability was 98%, superior to the control cultivar IAC 7 (93%), with a percentage of broken grain of 5%.The husk percentage was 33% and mean protein content 14.3%.
In relation to the main diseases in the evaluation regions, cultivar IPR Afrodite was moderately resistant to moderately susceptible to rust leaf (Puccinia coronata f.sp.avenae), stem rust (Puccinia graminis f.sp.avenae), and the leaf spot complex (Table 4), aside from moderately resistant to blast (Pyricularia grisea).The data of resistance to BYDV and scab (Gibberella zeae) were not conclusive.
In greenhouse experiments, cultivar IPR Afrodite proved superior over others (Table 5), for being moderately susceptible to Pratylenchus brachyurus, but highly resistant to four root nematode species of the genus Meloidogyne (M.incognita, M. javanica, M. paranaensis, and M. enterolobii).This motivated more detailed studies about the type of resistance of this cultivar.
Comparative penetration tests of M. incognita were performed with the cultivars IPR Afrodite (resistant) and URSFAPA Slava (susceptible).After germination, seedlings were inoculated with 1000 units of M. incognita and the root color was evaluated 3, 9, 15, and 30 days after inoculation (DAI).The number of nematodes within the roots indicated nematode penetration in both cultivars 3, 9 and 15 DAI, and the penetrated amount was lower in IPR Afrodite.Furthermore, juveniles stage J2, J3 and J4 were formed in  In conclusion, cultivar IPR Afrodite represents an excellent contribution to the oat production chain, with potentially high returns for farmers.The food industry will be supplied with high-quality grain for processing of many derivate products from this cereal, while consumers will have access to products with better quality, uniformity and flavor.

SEED PRODUCTION AND DISTRIBUTION
The oat cultivar IPR Afrodite is registered by the Brazilian registry of cultivars of MAPA, under number 28645 and a plant patent was issued by the Brazilian Plant Variety Protection service (SNPC, no.20130221), initiating the protection period as of 04/01/2013; IAPAR is in charge of seed production and marketing.

Table 2 .
Means of different agronomic traits of cultivar IPR Afrodite, evaluated in regional and nation-wide tests of oat inbred lines, from 2008 to 2010

Table 5 .
Reproduction factor (RF) and number of nematodes per grams of root (NGR) in oat genotypes, inoculated with Meloidogyne incognita, M. javanica, M. paranaensis, M. enterolobii, and Pratylenchus brachyurus, in means of greenhouse tests with 10 replications

Genotypes Meloidogyne in- cognita Meloidogyne javanica Meloidogyne para- naensis Meloidogyne enter- olobii
*Tomato for Meloidogyne spp.and sweet pepper for P. brachyurus.ǂ Means of RF and NGR, followed by same letters in a row, do not differ statistically by Tukey test at 5% probability.

Table 3 .
Means of grain yield (kg ha -1 ) of the new oat cultivar IPR Afrodite, compared to the two best controls of five years, at different test locations in Brazil

Table 4 .
Percentage of mean incidence of leaf rust (LR), stem rust (SR) and leaf spot (LS) on cultivar IPR Afrodite, evaluated for 3 years at 28 locations both cultivars 15 DAI.Obese females and egg masses were formed only in URSFAPA Slava, 30 DAI.No nematodes were found in the roots of IPR Afrodite at 30 DAI, indicating the death of juveniles between 15 and 30 DAI.