AGRONOMIJAS VĒSTIS - Latvijas Lauksaimniecības universitāte

AGRONOMIJAS VĒSTIS (Latvian Journal of Agronomy), No.10, LLU, 2008assessed per stem. The incidence and severity of fungal diseases were determined by the acceptedmethods, by % (Šurkus et al., 2002).Climatic conditions. The spring was warm in 2001: the average temperature in May was11.6˚C. There was high rainfall at the beginning of the summer (157 mm in June). In the spring of2002 warm and dry weather prevailed. At the beginning of summer there was sufficient warmthand moisture for the development of winter triticale. During the spring-summer period of 2004meteorological conditions for the development of cereals and perennial grasses were satisfactory,since the amount of rainfall was 20% lower than the long-term mean. The autumn was warm andwet. In 2005 the spring and beginning of summer were drier (rainfall only 80%) compared with thelong-term mean. The rainy second half of spring hindered cereal harvesting.The results were processed by the analysis of mean, standard error of mean, correlation,regression, variance, LSD tests applied.ResultsGrain yield in cereals depends on such yield component as: number of grains per ear, grainweight per ear and 1000 grain weight. A strong mutual corelation is usually found between thesecomponents. However, a limitation of one component can not be completely compensated for bythe others. According to the research data cultivar ‘Tewo’ has more grain per ear on average (Table1). Taking the average of two years, the cultivar with the highest weight of 1000 grain was ‘Alzo’(38.8±1.50 g) and the grain weight per ear of this cultivar was the biggest compared with thecultivars ‘Tornado’ and ‘Tewo’ grain weight.Table 1. The yield forming elements of different triticale cultivarsCultivar ExperimentalYield structure elementsyear Number of grain per ear Grain weight per ear, g 1000 grain weight, gTornado 2001 32.1±0.12 1.34±0.02 37.3±0.812002 38.7±0.58 1.46±0.07 36.5±1.10Average 35.4±1.36 1.40±0.04 36.9±0.63Alzo 2001 41.8±0.33 1.69±0.01 36.9±0.632002 29.3±2.40 1.33±0.06 41.8±2.30Average 35.6±2.69 1.51±0.06 38.8±1.50Tewo 2001 42.9±1.04 1.27±0.04 38.8±1.502002 38.1±1.63 1.45±0.05 33.6±0.39Average 40.5±1.27 1.36±0.05 36.2±0.26During the experimental period in 2001–2002 the most common diseases of winter triticalewere leaf rusts (causal agent Puccinia dispersa Rob. ex Desm. f. sp. tritici Eriks. & E. Henn.),septoria glume blotch and septoria leaf blotch (causal agent Stagonospora nodorum (Berk.) E.Castell et. Germano and S. tritici in Desmaz.), tan spot (causal agent Drechslera tritici-repentis(Died.) Shoem.), scald (causal agent Rhynchosporium secalis (Oudem) J. Davis). The observedwinter triticale cultivars differed in susceptibility to leaf rust and septoria leaf blotch (Table 2).During all the experimental years cultivar ‘Alzo’ was most resistant to these diseases comparedwith ‘Tewo’ and ‘Tornado’. The cultivar ‘Tewo’ showed a high susceptibility to diseases, and thecultivar ‘Tornado’ exhibited medium resistance to septoria leaf blotch and good resistance to leafrust. Leaf rust was one of the main diseases in winter triticale ‘Tewo’ in 2001 and 2002. Rustincidence at the triticale stage of stem elongation (BBCH 55) was 66.9%, severity – 3.01%, and atthe flowering stage all leaves were affected by 100%, but the first symptoms of leaf rust werespotted only at the triticale milk ripe stage (71 BBCH) in 2002 (Table 2). Septoria leaf blotch atearly growth stages prevailed on all triticale cultivars, but the cultivar ‘Tewo’ was affected most ofall, compared with other cultivars (Table 2). The relationship between the cultivar ‘Tewo’ yield anddisease severity was strong (r = –0.850) in 2001 and, due to the low development of diseases, itwas weak (r = –0.390) in 2002.124