CD 1252 : HEALTH , QUALITY AND TOLERANCE TO PRE-HARVEST SPROUTING CD

Resulting from the search for wheat cultivars with high yield potential, plant health, processing quality and tolerance to pre-harvest sprouting, CD 1252 was developed from the cross between cultivar IPR 85 and line OR1/3/BOW/GLENSON//BAGULA. Cultivar CD 1252 was tested in preliminary grain yield trials in 2005 and 2006, and then tested to determine the Value for Cultivation and Use (VCU) from 2007 to 2014, labelled CD 0711. All tests were arranged in an experimental design of randomized blocks, with three replications. The yield of cultivar CD 1252 was 5%, 4% and 1% higher than the average yield of the two best controls, respectively, in the wheat-growing regions VCU 2, 3 and 4. The wheat quality, potential for grain yield, and tolerance to pre-harvest sprouting of this cultivar are superior and it is tolerant to the main wheat diseases.


INTRODUCTION
Wheat breeding programs have significantly improved grain yield and other relevant traits (KOHLI, 1998), of which the processing quality has come to be a key factor in recent decades in Brazil.Currently, wheat breeding programs in Brazil are focused on the improvement of grain yield potential, processing quality and disease resistance.
For Mandarino (1993), the quality requirements were decisive for some improvements in wheat breeding programs because, aside from the traditional selection criteria (increased yield, and resistance to diseases and toxic elements), the grain quality traits, that are relevant for food processing and industry, have to be take into account in the development of new superior genotypes.
Quality maintenance at harvest is strongly related to tolerance to pre-harvest sprouting of a cultivar.Per Bassoi (2004), if rain falls before and during harvest, losses by germination are great, indicating the importance of using cultivars tolerant to pre-harvest sprouting in Brazil.To meet these essential prerequisites in the search for wheat lines with high quality, yield potential and pre-harvest sprouting tolerance, this study aimed to develop the CD 1252 cultivar.

CONTENTS
The CD 1252 cultivar was derived from the cross between cultivar IPR 85 and line OR1/3/BOW/GLENSON//BAGULA, made by COODETEC in 1999, in Palotina, State of Paraná.The F 1 seeds were sown in November 1999, in a greenhouse in Cascavel, producing F 2 seeds.The F 2 population was grown in 2000, in Cascavel, applying the mass selection method.The F 3 , F 4 and F 5 populations were selected, respectively, in 2001, 2002 and 2003 by the pedigree method.In 2004, the F 6 population was also selected by the pedigree method and the plots with regular plants were harvested in bulk, resulting in multiple sister lines.The best of these lines originated cultivar CD 1252.The pedigree of this line is CC15212-0T-3P-4P-9P-0P.
The CD 1252 cultivar was included in the preliminary trials of grain yield in Cascavel andPalotina, in 2005 and2006.For its performing better than the controls, it was evaluated in tests of Value for Cultivation and Use (VCU), from 2007 to 2014, under the acronym CD 0711.The VCU tests were carried out at representative locations of the wheatgrowing regions (CUNHA et al., 2006) The experiment was arranged in a randomized block design, with three replications, in plots consisting of six 5-m-long rows, spaced 0.20 m apart.The fertilization and pest and disease control were applied as officially recommenced (COMISSÃO, 2010).Prior to sowing, the seeds were treated with triadimenol and imidacloprid.The traits grain yield, days from emergence to heading, days from emergence to maturity, plant height, lodging, hectoliter weight, 1000-grain weight, gluten strength, and yield stability were assessed.At strategic locations, the genotype collections used in the VCU tests were planted, in which the observed shoot diseases, i.e., leaf rust, leaf spot, powdery mildew, head blight, scab and wheat mosaic virus, among other diseases, were not controlled.
A comparison of the mean grain yield in the wheat-growing regions VCU 2, 3 and 4, respectively, showed that the grain yield of the CD 1252 cultivar exceeded the average of the two best controls by 5%, 4% and 1% (Table 1).Due to the excellent performance of cultivar CD 1252, it was indicated for cultivation in the above regions, corresponding to the States of Parana, Mato Grosso do Sul, São Paulo, Mato Grosso, Goiás, Minas Gerais, and the Federal District (BRASIL, 2015).The CD 1252cultivar has a low average plant height (between 68-90 cm, mean of 75 cm).The cycle is average, lasting from 55 to 80 days from emergence to heading and 99 to 132 days from emergence to maturity (in the mean 66 and 116 days, respectively).CD 1252 has moderately resistant to lodging and to pre-harvest sprouting.In the means of the analysis of the processing quality of 32 samples from the tests in the different States, gluten strength was in the mean 340 W and stability 16.2 minutes, including CD 1252 in the extra strong wheat class.
In the experiments, carried out in the field from 2007 to 2014, data of several wheat diseases were recorded.CD 1252 was classified as moderately resistant to powdery mildew (Blumeria graminis f.sp.tritici), leaf spots (Bipolares sorokiniana and Septoria tritici), glume blotch (Septoria nodorum), leaf rust (Puccinia triticina), and wheat blast (Pyricularia grisea).In view of the high disease incidence, the cultivar was classified as susceptible to head blight (Fusarium graminearum).Cultivar CD 1252 is classified as extra strong wheat, has a high yield potential, tolerance to pre-harvest sprouting and to the major wheat diseases.It represents a promising option for Brazilian wheat growers.