UEL 175 : a novel lipoxygenase-free soybean cultivar with kunitz trypsin inhibitor absence

UEL 175 is lipoxygenase-free soybean cultivar and has absence of the antinutritional factors kunitz trypsin inhibitor (SKTI). UEL 175 presents high yield potential and good adaptation under no-tillage. It is resistant to soybean stem canker, brown stem rot, frogeye leaf spot, and bacterial pustule.


INTRODUCTION
Soybean [Glycine max (L.) Merrill] is considered as a high quality source of oil and protein for food and feed.However, lipoxygenases develops undesirable grassy and beany flavors in foods containing soybean due to oxidation of polyunsaturated fatty acids.Thus, soy products made of soybeans with lipoxygenases-free seeds have shown improved flavor characteristics (Hajika et al. 1991, Hajika et al. 1992, Carrão-Panizzi and Kitamura 1995).Moreover, raw soybean cannot be used for monogastric animal feeding due to the presence of factors that decrease its nutritional value.Among the antinutritional factors present in soybean seeds, the main one is the protease inhibitors kunitz trypsin inhibitor (SKTI), which is usually inactivated by heat treatment.However, heat treatment does not completely eliminate SKTI, and it may considerably decrease protein solubility.Eliminating this antinutritional factor, and obtaining lipoxygenase-free soybean varieties are of great importance and are desirable for the feed and food industry.
The soybean breeding program currently in progress at the Agronomy Department of Londrina State University, Londrina -PR has focused not only on yield, but also on quality improvement of soy-derived products used for feed and food.
The individual 293 of the F 2 generation was analyzed genotypically with polymorphic SSR molecular markers for null alleles for lox1, lox2 and lox3 enzimes (Lenis et al. 2010, Mandal et al. 2013).The F 2 generation lacking SKTI was analyzed with specific PCR primers for selecting seeds which lacked the SKTI protein.The primer sequences are as follows: forward: 5′ -CTTTTGTGCCTTCACCACCT-3′; reverse: 5′-GAATTCATCATCAGAAACTCTA-3′ (Moraes et al., 2006).The F 2 generation was also analyzed by SDS-PAGE in order to confirm the genotypes of the F 2 selected seeds.The F 2 generation was phenotyped by SDS-PAGE, which are colorimetric assays for seed lipoxygenase and SKTI status, confirming the genotypes of the F 2 selected.The F 2 generation was cultivated in the field, and the harvest was carried out by single seed descent method (SSD).

PERFORMANCE
UEL 175 cultivar had an average yield of 3.294 kg/ha in 3 experiments carried out in the 2009/1, 2010/11 and 2011/12 agricultural years in Londrina, Ponta Grossa, and Guarapuava.UEL 175's yield performance was inferior to BRS 284, which has indetermined growth, but it was 0.91 % higher than BRS 232, which presents determined growth and was used as control (Table 1).The potential of UEL 175 is being lipoxygenase-free and lacking the antinutritional factors kunitz trypsin inhibitor (SKTI).This seed line works as parents to develop elite breeding populations for breeding programs aiming at quality improvement of soy-derived products used for feed and food.Results of preliminary feeding trials, with chicks and young pigs, revealed that gain/feed was significantly higher when using lines lacking the kunitz trypsin inhibitor than when using cultivars containing the inhibitor (Hymowitz 1986).

OTHER CHARACTERISTICS
UEL175 has determined growth, plant height exceeding 82 cm, and high resistance to lodging pod dehiscence.It flowers at 58 days on average, and reaches harvest maturity at 120 days after emergence; it belongs to maturity group 6.7, and 100 seeds weight is 16.42 g.The oil and protein percentual contents are 21.63% and 38.54%, respectively.UEL 175 cultivar has white colored flowers, gray pubescence and pod, and bright and yellow seed coat.
UEL 175 is resistant to soybean stem canker, caused by Diaporthe phaseolorum f. sp.Meridionalis, to brown stem rot and frogeye leaf spot, caused by Cercospora sojina, and to bacterial pustule, caused by Xanthomonas axonopodis pv.glycines.

MAINTENANCE AND DISTRIBUTION
Breeder seed of UEL175 is maintained by the State University of Londrina.Small amount of seeds are available for research purposes at the Universidade Estadual de Londrina, Departamento de Agronomia, Campus Universitario, Londrina-PR, Rodovia Celso Garcia Cid, PR 445, km 380, Box 6001, 86.051-990, Londrina, PR, Brazil.
The F 3 generation plants were harvested in bulk, and CropBreeding and Applied Biotechnology 15: 191-192, 2015    V Carpentieri-Pipolo were designated UEL 04-175.During the 2006/2007 season, in F 3 , plants were grown at UEL, using the bulk method to advance the generation.During the 2007/2008 season, in F4, the individual plant was selected, and was evaluated as a progeny in the 2009/2010 season (in F 6 ) with the name of UEL 175.From F 7 generation on, UEL 175 cultivar was included in several regional trials carried out in Paraná (PR), and was released in 2013.