Genetic analysis of two terpenoid variants in cotton (Gossypium hirsutum L.)

We conducted genetic analysis of two terpenoid aldehyde (TA) variants transferred to G. hirsutum L. A high level of methylation (ME) was transferred from G. barbadense L. by direct backcrossing to G. hirsutum. Raimondal accumulation (RA), unique to G. raimondii Ulbr., was transferred by producing a synthetic amphidiploid and backcrossing to G. hirsutum. Progeny tests of the two TA variants were conducted in the field to ensure that the phenotypic expression was repeatable under field conditions and that plants used in the genetic analysis were homozygous. The TA variants were crossed on to TM-1 are the F1 TA profiles were determined. The F1 with the ME line had a wild-type (WT) TA profile that indicated that ME was recessively inherited. The F1 was self-pollinated to produce an F2, and the F1 was crossed with the ME line to produce a backcross (BC). Segregation in both populations confirmed that ME was conditioned by a single recessive allele, and we assigned it the symbol meme. The F1 with the RA line expressed raimondal that indicated that RA was dominantly inherited. The F1 was self-pollinated to produce an F2, and the F1 was crossed to TM-1 to produce a BC. Segregation for the RA variant was complex. In the F2, segregation was 9 raimondal: 7 none, and in the BC segregation was 1 raimondal: 3 none. This segregation conformed to the segregation of alleles at two loci with epistasis in which a variant allele has to be present at both loci before raimondal is produced. We assigned the gene symbols Ra1Ra1Ra2Ra2 to the RA variant. Linkage tests were conducted with virescent-1 (v1), cup leaf (cu), glandless-1 (gl1), frego bract (fg), cluster-1 (cl1), Red plant (R1), Okra leaf (L2 degrees), Tomentum (T1), Petal spot (R2), Yellow pollen (P1), Yellow petals (Y1), Brown lint (Lc1), and Naked seed (N1). Neither of the TA variants showed any linkage with the markers in our tests.