Open AccessChromosome pairing in hybrids between hexaploid bread wheat and tetraploid crested wheatgrass (Agropyron cristatum)
Author(s) -
JAUHAR PREM P.
Publication year - 1992
Publication title -
hereditas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 50
eISSN - 1601-5223
pISSN - 0018-0661
DOI - 10.1111/j.1601-5223.1992.tb00212.x
Subject(s) - agropyron cristatum , pairing , biology , hybrid , bivalent (engine) , ploidy , chromosome pairing , agropyron , genome , botany , common wheat , meiosis , genetics , chromosome , gene , physics , superconductivity , organic chemistry , quantum mechanics , metal , chemistry
To transfer drought and cold tolerance from crested wheatgrass, Agropyron cristatum (2n = 4x = 28; PPPP genomes) to bread wheat, Triticum aestivum (2n = 6x = 42; AABBDD), intergeneric hybrids (2n = 5x = 35; ABDPP) were synthesized. The F, hybrids were perennial like the male wheatgrass parent. Their morphology was almost intermediate between the two parents. A low‐pairing (LP) hybrid and a high‐pairing (HP) hybrid were studied. The LP hybrid, with apparently functional Phi (the pairing regulator that suppresses homoeologous pairing), had a mean of 0.14 III + 1.16 ring II + 3.17 rod II + 25.91 I, with a c (the mean arm‐pairing frequency) of 0.206. If A , cristatum were an autotetraploid, its haploid complement (PP) in the hybrid should form approximately 7 II. The mean of only 4.33 II (of which about 1.0 bivalent probably involved the A, B and D genomes of wheat) would suggest a certain degree of divergence between the two P genomes. The HP hybrid had 0.03 chain IV + 0.47 III + 2.98 ring II + 5.89 rod II + 15.73 I, with c = 0.460. Such a high pairing probably involved both autosyndesis (pairing within the ABD component and within the PP component of the ABDPP hybrid) and allosyndesis (pairing between the parental complements), and could have occurred only if Phl was partially inactivated. Homoeologous pairing of chromosomes of P with wheat chromosomes seems sufficient to facilitate the transfer of desirable traits of A. cristatum into wheat.