Utilization of wild species for improvement of cultivated f o m s has been investigated since Faircloth made the first interspecific hybrids in 1 7 1 7 , M a n y wild species have been of value in crop improvement for a large number of traits w a r l a n , 1 9 7 6 ; Hawkes, 1 9 7 7 ; Stalker, 1980a; Hadley and his article is a contribution from p a p e r No, 10726 of the J o u r n a l Series of +he North Carolina A~icu1tura.l Research Service, Rdeigh, North Carolina 27695, and P a p e r No, 635 o f the Journal Series of the X n t e r n a t i o d Crops Research Institute for the Senai-19rid Tropics (ICRISAI), Patanchcru, P -0 , -Andhra Pradesh 5 0 2 324. X n d i a -

SUMMARYTwo experiments to investigate the crossabilities of varieties of bread wheat, Triticum aestivum, with Hordeum bulbosum are described. In the first a range of varieties having low and high crossability with rye, Secale cereale, were used.It was found that a strong positive correlation between the crossabilities of wheat varieties with H. bulbosum and with rye exists.In the second experiment the genetics of crossability was investigated using chromosome substitution lines of the non-crossable variety, Hope, into the crossable variety Chinese Spring. Two chromosomes, namely 5A and 5B of Hope, were found to reduce markedly the crossability of Chinese Spring. These chromosomes were those identified by Riley and Chapman (1967) as being responsible for the crossability of Chinese Spring with rye, reinforcing the conclusion that the crossability of wheat with both species is governed, at least in part, by the same genetic system. However, other chromosomes were also shown to affect the crossability of Chinese Spring, although to a much lesser extent. The use of this interspecific cross to produce wheat dihaploid lines for breeding purposes is discussed.

No abstract

An interspecific hybrid between Cicer arietinum cv. GL 769 and a wild species C. pinnatifidum was obtained after emasculation, pollination and application of growth regulators. Ovules were cultured and embryos were later dissected to obtain hybrid plants. These plants were albinos and morphologically resembled C. pinnatifidum. Shrivelled seeds were also obtained in 2% of the crosses, which on germination gave rise to albino plants. These plants did not survive beyond 20 days. The hybrid nature of these plants was confirmed by esterase isozyme studies. Hybrid shoots obtained from germinating embryos were cultured on modified ML-6 medium with BAP 2 mg/1, IAA 0.5 mg/1, where they turned green after 3-4 weeks. Transmission electron microscopy (TEM) studies on leaf sections from green hybrid shoots showed an improvement in the chloroplast structure, with better organized grana.

7'hcc~ulti~utedpc~a,r1~/ (Arachis hypogaea. Fubaccac) is belic~ved to have orlginutcjd ulorrg I/?(, C~U S I C~I I slo/)c,s (?f ihr ..lnrl(s in Bo111.ia und northerr1 Argentina. The crop 1s t~orc groLt,tr thronghout i r o~~i c~u l utid warm tonpiJralr regron.c. .4rnong diseases uttac.krn,q pc,ut~lrrs, rlitr cwlr.,c~/ hjl Puccinia arachidis arid larr, Ieuf'spot cuuscd hj, Phaeoisariopsis personata urea flic r?io.sl rt?iportan/ and dcstrurttvc~ on a ~, o r l d~, i d r .\c,olc. noti? pa//iogc,tr~, rr,stric./cd rn host run@, to Arachis, prohahly originated and c,oc,vol\,ed irl .Siiut/r .,ltnrriiu alclt~y ~i'ith thrir /~ost.s. In rcwnr years there has heen 1?11i(./r ~rtlphusr.\