Abstract only

It was proved that in all crops, including cereals, plant height as well as lodging-resistance has significant importance in producing input- responsive varieties that will further ensure high productivity and high quality germplasm. Loss of yield due to lodging of plants reaches approximately 60% (V.Dorofeev, 1960). Lodging degrades quality of grain, reduces accumulation of dry substances, lowers gluten content as well as baking properties. (Naskidashvili et al., 1983). Analysis of publications on breeding of Triti- cale has clearly demonstrated that there is little scientific research related to this new culture, and therefore, we believe it reasonable to publicize the methods of our research of breeding of Triticale, which are the same as commonly used for wheat. Development of short-stem species of Triticale is, in fact, a reconstruction of its morphology. The plants should combine such key characteristics as lodging resistance, productivity of spike as well as beneficial harvest index. It can be suggested that such modi- fication of Triticale plant morphology is a new way to increase yield. Producing high yielding, input-responsive short-stature Triticale germplasm in Georgia is an urgent issue aimed at introduction of this crop into the fanning practice. The world nurseries of Triticale and Georgian wheat are the most valuable germplasm to work with. Plant height inheritance pattern is not similar in the first generation hybrids, produced through crossing of octaploid and tetraploid Triticale with Georgian aboriginal wheat. In the first generations the authentic heterosis is rarely observed. Intermediate heredity was mainly observed, as well as relative heterosis (hypothetic heterosis) and depression in case of small number of the combinations. Improved types are produced when bread wheat is taken as a mother plant. In crossing of octaploid Triticale with bread wheat, heterosis was developed in 172 combinations out of 177, that is 97% of hybrid combinations. In hybrids of this group the plants are taller when a tall plant is taken as a mother. In the second-generation hybrids in addition to other characteristics transgression in plant height was noticed. The hybrids produced through crossing of octaploid and hexaploid Triticale with bread wheat are quite variable in height: in case of octapolid Triticale their height varied within 55-152 cm, in case of hexaploid Triticale within 75-175 cm, which is caused by the activity of one, two and three genes determining short-stature. In the second generation, many of the plants bear lodging resistant stems, thick and well-grained spike and are highly productive. Study of plant height in Triticale goes in two directions. The first direction is to develop forage Triticale with tall, lodging-resistant stem, and the second aims at development of grain types, with a lodging-resistant stem of 90-100 cm height. Study of plants in second generations of the hybrid populations has proved that majority of hybrid populations offer opportunity to select plants of desired type within populations of both the first and the second generations. Thus, in crossing of model species of Triticale with the varieties of Georgian bread wheat very interesting segregating hybrid populations are produced, offering an opportunity to select comparatively tall, lodging-resistant, thick and generously leafed breeding material for development of the input-responsive varieties. For this purpose the best donor varieties are Georgian wheats Akhaltsikhis Tsiteli, Dolis Puri, Khulugo, Tbilisuri 5 and Mukhranula 7, as well as octaploid Triticale varieties Hungarian K-43235, Polish K- 44925 and hexaploid variety Triticale Hungarian K-396170.

English

0409|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection