. In: Heady , Patrick — Grandits , Hannes (eds.), Distinct Inheritances: Property, Family and Community in a Changing Europe , 263–274. Münster: LIT.
Distinct Inheritances: Property, Family and Community in
Authors:D. Yadav, S. Gupta, V. Kulkarni, K. Rai and R. Behl
Inheritance of male sterility and fertility restoration of the A
system of cytoplasmic-nuclear male sterility in pearl millet was investigated using 12 crosses among three diverse male sterile lines (A-lines) and four diverse restorers (R-lines). Individual plants from R- lines were used to make crosses on A-lines. The segregation pattern of male sterile (S) and male fertile (F) plants observed in F
in two seasons at ICRISAT, Patancheru was suggestive more likely of a single-gene control of male sterility and fertility restoration. However, a 3-gene model of male sterility/fertility restoration where dominant alleles at any two of the three duplicate complimentary loci will lead to male fertility could not be ruled out, nor could be ruled out a 2-gene control with duplicate interaction. There was indication of variability even within a highly inbred R-line for fertility restoration gene(s). Depending on the genetic constitution of the R-lines at these loci, even the 3-gene model can lead to single-gene segregation ratios as observed in most of the F
and backcrosses, and 2-gene ratios as observed in a few F
and backcrosses. The deviations from these expected ratios in some of the crosses influenced by modifiers and environmental conditions generally resulted from the excess of fertile plants in the rainy season or excess of sterile plants in the dry season, the more so in crosses involving an A-line which has been reported to be relatively more unstable for male sterility.
Brown planthopper (BPH) is one of the destructive insect pests causing significant yield losses in rice. BPH causes direct damage to the rice plants by sucking the sap from phloem, causing hopper burn and transmitting viral diseases like grassy and ragged stunt viruses. Several resistant donors have been identified from time to time, but the new biotypes of the pest arise to defeat the extended use of resistance genes in a single variety. This necessitates the regular identification of new resistant donors along with their nature of inheritance and gene action controlling the resistance. Knowing the inheritance pattern, gene action and number of genes controlling a trait helps the plant breeders to plan the effective breeding approaches for crop improvement. The present investigation was hence carried out to know the inheritance pattern, gene action and number of genes controlling BPH resistance in newly identified sources. The results indicated that the BPH resistance in PHS 29 genotype is under the control of single recessive gene. Whereas, it is controlled by two recessive genes in MRST 3 genotype. This reveals that relatively higher population size will be required to recover desirable segregants in the segregating populations involving MRST 3 genotype as one of the parents as compared to that involving PHS 29 genotype as parent. Since, the resistance in both the cases being recessive in nature, the trait will hence show significant additive effect, indicating that pure line development will be desirable for improvement of such a trait.
Authors:R. Paliwal, B. Arun, J. Srivastava and A. Joshi
The objective of this study was to develop an understanding about the genetics of terminal heat tolerance in wheat (Triticum aestivum L.). The minimum number of genes was assessed using Mendelian and quantitative genetic approach. Two crosses were made between heat tolerant and heat susceptible bread wheat cultivars: NW1014 × HUW468 and HUW234 × HUW468. Heat susceptible HUW468 was common in both the crosses. The F4, F5 and F6 generations were evaluated including F1 in two different dates of sowing (normal and very late) under field conditions in year 2006–07. The data was recorded for grain fill duration (GFD) and thousand-grain weight (TGW). Based on data of two dates, decline% and heat susceptibility index (HSI) of GFD and TGW were estimated. Heat tolerance in F1 showed absence of dominance. Estimation of genes using Mendelian approach in F4, F5 and F6 progenies (148–157) of the two crosses suggested that heat tolerance was governed by a minimum of three genes. Quantitative approach also indicated similar number of genes. The distribution of progeny lines in F4 and F6 supported the polygene nature of heat tolerance. These genes if mapped by molecular approach can play an important role through marker assisted selection (MAS) for developing improved thermo-tolerant lines of wheat.