KARYO-RACES IN SPINACIA OLERACEA

Bose , Smritimoy , and Jules Janick . (Purdue U., Lafayette, Ind.) Karyo-races in Spinacia oleracea. Amer. Jour. Bot. 48(3): 238–241. Illus. 1961.—Cytological analysis of chromosome 1 of Spinacia oleracea, which contains the XY factor pair, revealed the existence of 3 distinct morphological types. The “standard” chromosome 1, the longest of the complement, is heterobrachial with one arm being about twice as long as the other. The most prevalent situation is for this “standard” chromosome pair to be homomorphic in staminate, monoecious, or pistillate plants. Some staminate and pistillate plants in the varieties ‘Spica’ and ‘Universal’ were found to be heteromorphic for the standard chromosome and a variant type, distinguished by a satellite on the short arm. In a cross derived from an accession PI 169671 from Turkey, which segregated for monoecious and pistillate types, half of the plants, irrespective of sex, were homomorphic for the standard chromosome and half were heteromorphic. The non-standard chromosome was longer and isobrachial, the added length apparently due to an additional segment on the short arm of the “standard” chromosome. Plants homomorphic for the satellited and isobrachial chromosome have been obtained.