Оценка на вредата, причинена от Bruchus pisorum L (Coleoptera: Chrysomelidae) върху някои показатели, свързани с качеството на семената при сортове фуражен грах (Pisum sativum L.)

It was evaluated the damage caused by Bruchus pisorum L (Coleoptera: Chrysomelidae) on the germination ability of pea farage varieties (Pisum sativum L.). Result of damage by Bruchus pisorum in seeds with parasitized larva was significant decrease of the germination by 16.4% percentage points, the length and weight of primary radicle by 16.8 and 24.5%, the length and weight of plumule by 12.3 and 14.1%, the vigor index of primary radicle and plumule by 32.5 and 32.8% as well as the germination index by 17.4%. The inhibitory effect was on average 17.8%. Essential significant changes in regard to the studied parameters were found for damaged seeds with bruchid emergence hole. In these seeds the gewrmination decrease by 58.3% percentage points, the length and weight of primary radicle by 34.1 and 36.2%, the length and weight of plumule by 31.8 and 34.3%, the vigor index of primary radicle and plumule by 81.1 and 82.1% as well as the germination index by 83.1%. The inhibitory effect was on average 58.3%. It was found that the damaged seeds with parasitoid emergence hole provided better possibility for growth and development of plants whereas the damaged seeds with bruchid emergence hole had significantly low germination, vigor and sowing characteristics. These seeds could not provide the establishment of well-garnished stand and stable yields. As tolerant to damage by Bruchus pisorum was distinguished Glyans variety for which the values of parameters related to germination and vigor of seeds were influenced in the lowest degree from the damage unlike the sensitive Pleven 4 variety. Dominant factor influencing germination ability of seeds for all analyzed parameters was the type of seeds compared to varietal appurtenance.През 2012г. опитното поле на Института по фуражни култури – Плевен е изведен опит с 5 сорта пролетен фуражен грах Глянс; Модус; Камертон и Свiт (украински сортове) и Плевен 4 (български сорт, стандарт). Направена е оценка на вредата, причинена от Bruchus pisorum L (Coleoptera: Chrysomelidae) върху кълняемата способност на сортовете грах (Pisum sativum L.). Резултат от вредата на B. pisorum при семена с паразитирана ларва е доказнано намаляване на кълняемостта средно с 16.4%тни единици, дължината и теглото на първичния корен с 16.8 и 24.5%, дължината и теглото на кълна с 12.3 и 14.1%, индекса на жизненост на първичния корен и кълн с 32.5 и 32.8%, както и индексът на кълняемост със 17.4%. Инхибиращият ефект е средно 17.8%. Съществени доказани промени по отношение на проучваните показатели се установяват при повредените с прозорче от имагинирал зърнояд семена, при които кълняемостта намалява с 58.3% тни единици, дължината и теглото на първичния корен с 34.1 и 36.2%, дължината и теглото на кълна с 31.8 и 34.3%, индекса на жизненост на първичния корен и кълн с 81.1 и 82.1%, както и индексът на кълняемост със 83.1%. Инхибиращият ефект е средно 58.3%. Установено е, че повредените с прозорче от имагинирал паразитоид семена осигуряват по-добра възможност за растеж и развитие на растенията, докато повредените с прозорче от имагинирал зърнояд семена са с доказана ниска кълняемост, жизненост и посевни качества. Тези семена не могат да осигурят създаването на добре гарниран посев и стабилни добиви. Като толерантен към повредите от B. pisorum се очертава сорт Глянс

Stem formation at alfalfa varieties and correlative dependences with some main parameters

During the period 2006-2009 in IFC-Pleven were studied 9 alfalfa varieties: Europe, Prista 2, Prista 3, Prista 4, Obnova 10, Pleven 6, Dara, Multifoliate and Dama. In the first year of its development alfalfa formed on average 1.42 number of stems per plant. During second and third year their quantity increased to 2.14 and 3.83 number whereafter during fourth year they decreased to 3.28. In all years (except the first year) was found a trend of increase in stem number from spring to autumn regrowth with average values 2.11, 2.85 and 3.05 respectively. Average for the four-year period the greatest number of stems (over the average for the nine studied varieties – 2.67) formed the Multifoliate variety followed by Europe, Prista 4, Obnova 10 and Dama. The varieties which are characterized by less density of stand (number of plants per unit area) had a greater number of stems per plant (r = -0.530). Correlations with mean and high positive value were found between stem formation and amount and distributions of rainfall during vegetation period (r = 0.989), year of alfalfa development (r = 0.861), nodulation (r = 0.763), weight of root mass (r = 0.411) as well as correlations with mean negative value between number of stems and percentage of damaged stems by Apion seniculus (r = -0.456)

Nutritive value responses to biological products in alfalfa forage (Medicago sativa L.)

The effects of the biological insecticides Madex and Agricolle, applied alone or in combination with the biological fertilizers Lithovit and Nagro, on chemical composition and enzyme in vitro digestibility, as well as energy feeding value of alfalfa dry mass were studied. Treatments were carried out at the beginning of the flowering stage during the second cutting for control of economically important pests, testing a method of organic pest control. Independent and combined applications of several biological products were found to influence positively the chemical composition, enzyme in vitro digestibility, and energy and protein nutritional value of alfalfa feed. An optimal combination of decrease in the content of plant cell wall fiber components and a significant increase in forage enzyme in vitro digestibility was revealed after the application of Agricolle and a combination of Agricolle and Nagro. Digestibility reached 60.4 and 59.9%, respectively, which is an increase of 12.0 and 11.0%. Alfalfa low fiber, high protein content, and digestibility made a very good complement to grains and other forages in dairy rations after treatment with biological products

Response of Pea Varieties to Damage Degree of Pea Weevil, Bruchus pisorum L.

A study was conducted to determine the response of five pea varieties (Pisum sativum L.) to damage degree of Bruchus pisorum: Glyans, Modus, Kamerton, and Svit (Ukrainian cultivars) and Pleven 4 (Bulgarian cultivar). The seeds were classified into three types: healthy seeds (type 1), damaged seeds with parasitoid emergence hole (type 2), and damaged seeds with bruchid emergence hole (type 3) and they were sown. It was found that the weight of 1000 seeds did not affect the field germination of the pea varieties. Healthy and damaged seeds with parasitoid emergence holes (first and second seed types) provide a very good opportunity for growth and development while plants from damaged seeds with bruchid emergence holes had poor germination and vigor and low productivity. These seeds cannot provide the creation of well-garnished seeding and stable crop yields. Among tested varieties, the Ukrainian variety Glyans had considerably higher seed weight, field germination, and index germination and weak egg-laying activity of B. pisorum compared to others. Use of spring pea cultivars that are weakly preferred by the pea weevil in breeding programs would reduce losses due to pea weevil and provide an environmentally safer option to its control