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The Neoplasm trait in pea pods is reported to be due to the lack of ultraviolet (UV) light in glasshouse conditions or in response to pea weevil (Bruchus pisorum L.) damage. This pod deformation arises from the growth of non-meristematic tissue on pods of domesticated peas (Pisum sativum L. subsp. sativum). Neither expressivity, nor the effect of pea weevil on neoplasm in the tall wild pea (P. sativum L. subsp. elatius (M. Bieb.) Asch. & Graebn.), have been adequately studied. We aimed to study the expression and inheritance of neoplasm in the tall wild pea and crosses between domesticated and tall wild peas grown in the glasshouse (without pea weevils) and in the field (with pea weevils) under natural infestation conditions. Neoplasm was found in all pods in tall wild peas when grown in the glasshouse, while it was not detected on pods of field-grown plants despite heavy pea weevil damage. In inter-subspecific crosses between P. sativum subsp. sativum and P. sativum subsp. elatius, all F1 plants had neoplastic pods, and the F2 populations segregated in a good fit ratio of 3 (neoplasm): 1 (free from neoplasm) under glasshouse conditions, which suggests that neoplasm on pods of the tall wild pea was controlled by a single dominant gene. Expressivity of neoplasm in the progeny differed from parent to parent used in inter-subspecific crosses. There was no relationship between neoplasm and damage by pea weevil under heavy insect epidemics under field conditions. The neoplasm occurring under glasshouse conditions may be due to one or to a combination of environmental factors. Since wild peas are useful genetic resources for breeding programs aiming at fresh pea production that could be utilized under glasshouse conditions, negative selection could be considered in segregating populations.

No abstract

Thirty-four Turkish barley (Hordeum vulgare) varieties were tested for the presence of resistance genes (R-genes) to powdery mildew (Blumeria graminisf. sp.hordei) using the “leaf segment test” with nine isolates of the fungus. The most commonly found R-gene wasMla8, while a combination of R-genesMlgandMl(CP)was found in three varieties (Tokak 157/37, Beysehir 98, Konevei 98). The geneMlhwas found in four varieties (Obruk 86, Anadolu 86, Çıldır 02, Özdemir 05), while no R-gene was found in three varieties (Hamidiye 85, Yesevi 93, Bülbül 89). No clear inferences could be made for the partly-resistant varieties Gemici 7243, Yea 793.12 and Akhisar 98 using the test isolates selected, which suggests the presence of still unidentified R-genes. Overall, 10 previously characterized R-genes for powdery mildew (Mla8,Ml(La),Mlg,Ml(CP),Mlh,Mlat,Mla1,Mlh,Mla7,Mlra) were present in Turkish barley varieties, along with some other(s) still to be identified.

In a study of resistance to powdery mildew, we investigated three populations of Hordeum spontaneum using leaf segment test. For comparison of the reactions, we used 44 barley lines as differentials representing most of the resistance used in barley breeding. The H. spontaneum accessions were infected with 21 isolates selected for their reactions on the differential barleys. The results of H. spontaneum collections did not show any similarities with differential barleys used. Resistance reactions were very rare. There was no resistance to 13 out of the 21 isolates. Horizontal resistance was noticed in most of H. spontaneum lines