(go to KOMUGI Home) (go to WIS List) (go to NO.74 Contents)

Wheat Information Service
Number 74: 6-8 (1992)


Exploitaion of AAGG genomes of Triticum timopheevi (Zhuk.) Zhuk.

H. N. Pandey and D. Singh

Division of Genetics, Indian Agricultural Research Institute, New Delhi-1100 12, India


Introduction

Indian durums (T. turgidum L. var. durum ) have very narrow genetic base for yield and its attributes. Attempts are being made to improve the domestic varieties of durums by incorporating desirable traits from its related tetraploid species. Triticum timopheevi (Zhuk.) Zhuk. (AAGG) is one of them.


Materials and Methods

Two tall durum cultivars, NI 146 and MACS 9 were crossed as female parents with T. timopheevi strain. The F1 hybrids of these crosses were backcrossed to their tall parents, and then the B1 F1 plants were crossed with semidwarf durum cultivars, Raj 1555 and DWL 5023, respectively. The second backcross plants were raised in the field and plants with desirable traits were selected. After eight generations of selfing and selection several homozygous timopheevi derivatives (possessing several desirable agronomic traits) were selected. These lines possess good plant types in addition ot their high yielding ability.

After ninth generation, derivatives were evaluated for agronomic traits like seedling height, coleoptile length, seminal root number, plant height, heading date, grain yield, 1000 kernel weight and lodging tolerance.

From the test entries two sister lines B 138 and B 139 drived from the cross T. timopheevi x NI 1462 // Raj 1555 and the other two sister lines B 174 and B 180 derivatives of T. timopheevi x MACS 92 // DWL 5023 were compared with the best semidwarf durum cultivar PBW 34. For yield evalution, the derivatives were tested in two separately conducted (one for each set of cross) good fertility trials in which each entry was replicated three times, having a plot size of 1.38 x 6.0 m each.

To assess seedling height, coleoptile length and seminal root number, seeds of the lines B 138, B 139, B 174, B 180, T. timopheevi and PBW 34 (durum control) were germinated in the petridishes. Data were recorded after 8 or 9 days of imbibition on 20 seedlings in each case.


Results and Discussion

Mean values (Table 1) for various traits showed that the derivatives of T. timopheevi were shorter in seedling height than the control varieties. Plant height at maturtity in the field conditions maintained similar pattern in the derivatives. A good relationship between seedling height and plant height of B 139 suggests the possibility of selection of shorter seedlings possessing good root system from the petridishes. This way fairly a large material can be screened which otherwise may be difficult and time consuming task in the field conditions.

In the field conditions derivatives B 138 and B 139 produced 26% and 14.4% more grain yield than the control PBW 34, respectively. This increase in grain yield can be attrituted to the traits like shortening in the plant height, higher kernel weight, lodging tolerance and reduction in the heading days of these derivatives compared to control variety PBW 34 (Table 1).

Higher root number with reduced culm length in B 138 and B 139 appeared to be responsible for very strong straw in these deviratives resulting in high lodging tolerance even when the irrigation was povided during heavy winds in the season.

T. timopheevi line used in this programme was variety Viticulosum obtained from USSR. Looking into the encouraging results of derivatives, eleven timopheevi accessions received from different sources like U. K., USA, USSR and Israel are being used as donor to diversify the Indian durums.

(go to KOMUGI Home) (go to WIS List) (go to NO.74 Contents)