Monosomic alien addition lines derived from Glycine max (L) Merr and G-tomentella Hayata: Production, characterization, and breeding behavior

Utilization of exotic germplasm (16 wild perennial species of the subgenus Glycine Willd.) to broaden the genetic base of soybean [G. max (L.) Merr.] has been impeded because of extremely low intersubgeneric crossability. Our objective here is to report the production, identification, and breeding b ehavior of monosomic alien addition lines (MAALs) each with 2n = 40 chromos omes of soybean and one chromosome from G. tomentella Hayata (accession PI 483218, 2n = 78). Glycine tomentella contains genes controlling several eco nomically useful traits such as resistance to soybean rust (Phakopsora pach yrhizi Sydow) and soybean cyst nematode (Heterodera glycines Ichinohe) and tolerance to salt and drought. We have isolated 287 plants with 2n = 41 chr omosomes from PC, and BC4 progenies. On the basis of distinguishing morphol ogical features, these fines were grouped into 22 MAALs and were designated as MT-I to MT-XXII. MT denotes max and tomentella. The addition of an extr a chromosome of G. tomentella to the 2n soybean complement modified several morphological traits including flowering habit, plant height, degree of pu bescence, seed fertility, number of seed per pod and plant, pod and seed co lor, and seed yield. The female transmission of an extra G. tomentella chro mosome in MAALs averaged 36.5% and male transmission averaged 11.7%. This s tudy sets a stage whereby the germplasm treasure harbored in exotic germpla sm, the wild perennial relatives of the soybean, which was unexplored and n ot utilizable in the past, can now be reached by geneticists and plant bree ders.