Chromosomal effects on In Vitro morphogenesis in Wheat intervarietal Substitution Lines

Abstract

Common and dwarf bunt (Tilletia caries (DC.) Tul & C. Tul, T. foetida (Wallr.) Liro and T. controversa (Kühn) are potentially important wheat diseases in Romania, especially in organic farming and on small farms, unable in most cases to properly treat the seed. Growing bunt resistant cultivars can be an efficient way to reduce expenses and protect the environment, by reducing use of pesticides. For these reasons, a small breeding program was started in 1972, by crossing the old Turkish wheat PI 178383 (a Bt9 and Bt10 carrier) with adapted cultivars. Later, in an attempt to diversify the resistance genes used in the program, several gene sources (including Bt5, Bt8, Bt11, Bt12 etc.), received from Dr. Bob Metzger (Oregon State University, U.S.) were used as parents. Since, our research effort has focused on: (1) continuously checking the efficiency of known bunt resistance genes against local populations (isolates) of bunt; (2) improving the competitiveness of bunt resistant germplasm by repeated cycles of crossing with adapted cultivars and selection for both bunt resistance and agronomic type and (3) searching for new bunt resistance genes. (1) About ten years of artificial testing with 6-10 isolates/year of bunt collected from Romanian locations representative for natural occurrence of Tilletia species, has constantly shown that Bt5, Bt10, Bt11, Bt12 expressed a high level of resistance. Along with original sources provided primarily by Dr. Bob Metzger and more recently, also by Prof. Blair Goates (National Small Grains Germplasm Research Facility, West Aberdeen, U.S.), advanced lines carrying the most efficient genes were tested and confirmed the transfer of this trait. (2) All bunt resistance gene sources available to us were very tall, susceptible to powdery mildew and leaf rust, were low yielding and had poor baking quality. Progress in improving the competitiveness of bunt resistant lines in the absence of bunt has been slow, but every new cycle has shown definite improvements over the previous ones. Presently available bunt resistant lines are semidwarf and powdery mildew resistant, are better adapted to local conditions and give yields of 90-100% as compared with current check cultivars. They are still deficient in leaf rust resistance and bread making quality. New lines with improved leaf rust resistance and quality are in preliminary yield tests. Accelerated progress is expected by using molecular markers for some of the bunt resistance genes. Markers will also be used to pyramid resistance genes. (3) Search for new bunt resistance sources has identified two potential sources with resistance, presumably coming from the Brazilian cultivar Colonias and from the rye genome. Further testing with a wider range of bunt isolates is under way. Positive experience in accelerated selection of higher resistance to other wheat pathogens, accumulated from larger forms of trans-national cooperation (ring tests), emphasized the need of such approach with regard to common bunt, too. The XV th Biennial Work...

Modes of morphogenesis inheritance in vitro in strawberry (Fragaria x ananassa Duch.)

“…Most of the utility plant traits are polygenically-controlled quantitative traits. Reports based on the results of many authors indicate that the morphogenetic potential of plant cells and tissues is also a quantitative and, therefore, polygenic trait (Oleszczuk and Zimny 2000;Li et al 2003;Tyankova et al 2006;Dodig et al 2008). The genotype of the primary explant is the most important factor determining the effective regeneration of plants from callus in various monocotyledonous plant species (Mathias 1990;Li et al 2003).…”

“…Bhaskaran and Smith (1990) and Bregitzer and Campbell (2001) found that in vitro cereal morphogenetic abilities are inherited quantitatively. Tyankova et al (2006) and Oleszczuk and Zimny (2000) reported that the morphogenetic potential of plant cells and tissues was a quantitative trait, and thus polygenically determined. Hence, a thorough understanding of its genetic determinants is difficult and requires observation of the phenotypic expression of the trait in numerous populations and to conduct many genetic analyses using special research methods.…”

Genetic control of in vitro morphogenesis in wild strawberry (Fragaria vesca)

“…Reports based on the results of many authors indicate that the morphogenetic potential of plant cells and tissues is also a quantitative and, therefore, polygenic trait (Dodig, Zorić, Mitić, Nikolić, & Surlan‐Momirović, ; Li et al., ; Oleszczuk & Zimny, ; Tyankova et al., ). The results of the research carried out in this work also confirm the quantitative nature of morphogenetic potential inheritance of Fragaria vesca cultivars analysed in vitro.…”

“…Bhaskaran and Smith () and Bregitzer and Campbell () found that in vitro cereal morphogenetic abilities are inherited quantitatively. Oleszczuk and Zimny () and Tyankova, Zagorska, Chardakov, Dryanova, and Dimitrov () also have reported that the morphogenetic potential of plant cells and tissues is quantitative, and thus a polygenically determined trait. Hence, a thorough understanding of its genetic determinants is difficult and requires observation of the phenotypic expression of the trait in numerous populations and conducting many genetic analyses using special research methods.…”