New Earliness Index And Integration Of Earliness Additive Genes In The New Genotype Of Cotton (Gossypium hirsutum L.)

Abstract

ABSTRACT-Cotton (Gossypium hirsutum L.) is an important fiber crop in the world being used in the textile industry and over 90% of cotton grown in the world is upland cotton. An experimental design carried out for integration of earliness genes from sindose-80 to bulgare-557 during 2005 to 2016 in the Department of Botany, University of PuneIndia and Agricultural Research Center of Tehran-Iran. The first cross carried out between sindose-80 and bulgare-557 in 2005 and after crossing five years selection was done among segregated population till to F 5 . In 2011 the second cross carried out as a back cross between the new variety and sindose-80. Five years selection was also done after second cross. In 2016, the new earliness genotype compared with the five native and commercial cotton varieties in RCBD design. The criterion for earliness was a new earliness index of combined picking and day (CPD), which has been presented as a new earliness index in this paper along with EFD and FFT indexes. Mean comparison of traits such as three earliness indexes, boll per plant, micronaire and yield showed priority of the new earliness genotype. Comparison of the three earliness indexes indicated priority of CPD index, which is combined by both time and weight to the two conventional indexes such as EFD and FFT which are showing time and weight affects in the earliness respectively.

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“…These environmental effects can affect earliness criteria which are controlling by additive quantitative genes despite of dominant qualitative genes. For this reason CPD index is the best formulae for estimation of earliness in cotton for illustrating of genetic effect of earliness very well and also separates the effect of management and environmental effects which are playing as suppressing factors (Hosseini, 2017). For example if we are comparing the two new earliness genotypes by the same FFT= 0.75 but two different first picking dates as P1= 4 months and 5 months after germination for the genotype of I and II respectively, and last pickings have been done for both 7 months after germination.…”

“…This distinction between varieties is indicator when compared in replicated trials with identical planting dates. Some cultivars produce their first squares on node 5, while others have minimal fruiting squares until node 7 or higher (Hosseini, 2017).…”