Aegilops tauschii, as a spot blotch (Cochliobolus sativus) resistance source for bread wheat improvement. | [Pakistan Journal of Botany • 2007]

Author(s):

1. A. Mujeeb Kazi: National Institute of Biotechnology & Genetic Engineering (NIBGE), Faisalabad, Pakistan

2. Alvina Gul: National Institute of Biotechnology & Genetic Engineering (NIBGE), Faisalabad, Pakistan

3. Iftikhar Ahmad: National Agricultural Research Center (NARC), Islamabad, Pakistan

4. Mohammad Farooq: National Agricultural Research Center (NARC), Islamabad, Pakistan

5. Shamim Iftikhar: National Agricultural Research Center (NARC), Islamabad, Pakistan

6. Shahzad Asad: National Agricultural Research Center (NARC), Islamabad, Pakistan

7. Sumaira Rizwan: Quaid-e-Azam University, Islamabad, Pakistan

8. Hadi Bux: Quaid-e-Azam University, Islamabad, Pakistan

9. Roman Delgado: International Maize and Wheat Improvement Centre (CIMMYT), Mexico D.F. Mexico

Abstract:

Cochliobolus sativus the cause of Spot blotch, affects wheat crops across several environments globally with Bangladesh being represented as a major disease location. Accessional diversity in conventional germplasm was limited until the mid-eightees with BH-1146 being most popular. With the novel usage of exotic germplasm emerging in that decade, wide cross programs got popularity and the release of the intergeneric cross product "Mayoor" initiated additional efforts around this new genetic diversity resource of the wheat family Triticeae. Derivatives of Mayoor known as Chirya added another dimension and then on the scene came the D genome contribution of the diploid progenitor Aegilops tauschii (2n=2x=14). Synthetic hexaploid wheats (SH) derived from crosses between Triticum turgidum x Ae. tauschii (2n=6x=42; AABBDD) became a popular gemplasm source for tests against various wheat production constraints around biotic and abiotic stresses and these provided superior resistance to C. sativum either alone or also in SH x SH combinations due to gene pyramiding. From the earlier resistance scores of 9-5 vs 9-9 for susceptibility the SH germplasm was front 9-2 or 9-3 to pyramided lines with 2-2 or 3-2. The latter translated to the same 2-2 or 3-2 levels when these superior SH`s were crossed onto elite bread wheat cultivars susceptible to C. sativus. Further, the resistant stocks derived from both the interrgeneric and interspecific avenues gave seed finish readings of 1 or 2 vs the 4 or 5 susceptible germplasm scores. This paper elucidates data of the above three categories of C. sativum tests done under stringent field conditions over several years of evaluations.

Page(s): 1207-1216

DOI: DOI not available

Published: Journal: Pakistan Journal of Botany, Volume: 39, Issue: 4, Year: 2007

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