Location: Crop Genetics ResearchTitle: Comparison of growth, yield and fiber quality of the obsolete SA30 yellow leaf with four sets of modern yellow and green leaf near isogenic cotton (Gossypium hirsutum L.) lines
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2018
Publication Date: N/A
Interpretive Summary: The cotton crops ability to absorb light and produce lint is being studied in an obsolete yellow leaf line found in 1925. To better understand the genetic improvements in cotton that were made over the last 92 years we have crossed this yellow leaf into modern cotton lines. The yellow and green leaf lines we produced were compared in field studies to the obsolete yellow line and to each other. Cotton growth, yield, and fiber quality were measured. One of the first observations was that both the obsolete and the modern yellow leaf lines grew equally as slow when compared to the modern green leaf lines. Another interesting observation was that when looking at the bolls produced per plant, both yellow and green leaf representatives of the modern lines produced greater than 200% the bolls produced on the obsolete yellow line. Similarly, plot yield in all but two cases exceeded the obsolete yellow leaf line by over 200% increases. The two which did not exceed were both modern yellow leaf lines with 167% and 192% greater yields. These findings are very promising because the purity of these modern lines can facilitate the identification of important genes associated with the increases in boll and fiber production. Identification of specific plant mechanisms that favor cotton boll/lint production could greatly benefit the U.S. farmers with improving yields.
Technical Abstract: The Virescent Yellow leaf cotton line Seed Accession 30 (SA30) was crossed with four modern parental lines (DP5690, DES119, SG747 and MD51ne) to develop four sets of near isogenic lines (NILs) segregating for green and yellow leaves. Comparisons of these lines were made in the field in a two year replicated study between the obsolete SA30 line and the four modern NIL sets. Yield measurements, including hand (bolls/plant) and machine harvested (kg/plot) samples, of the four modern NIL sets compared to SA30 resulted in a twofold difference except for DP5690 yellow leaf (192%) and MD51ne yellow (167%) in the kg/plot ratios. Other yield measurements (seed cotton wt. and 100 boll seed wt.) reflected the “Mebane” cotton background of the SA30 line with larger bolls, while lint yields reflected the higher lint percentages of the modern NILs. Growth parameters including plant height and number of nodes were measured at predetermined intervals and height to node ratios were determined with the green leaf lines growing faster than the yellow leaf lines. The yellow leaf NILs and the SA30 line grew at the same rate. Cotton fiber quality was measured with both AFIS and HVI and both similarities and differences are reported in the paper. The NILs used in this study were created to facilitate the discovery of the mechanism for increasing dry matter partitioning into reproductive growth in cotton.