Yield responses of some economically important crop plants due to foliar applications of low concentrations of 28-homobrassinolide (HBR) were studied in experiments conducted at research stations and in farmers' fields in India during 1989-95. Foliar sprays of different concentrations of HBR were applied at tillering and spike\panicle initiation in wheat (0n5 and 1n0 mg\l) and rice (0n25, 0n50 and 1n00 mg\l) ; at flowering and pegging in groundnut (0n25 and 0n50 mg\l) ; 30 and 45 days after sowing (DAS) in mustard (0n25 and 0n50 mg\l) ; 25 and 35 days after emergence in potato (0n25 and 0n50 mg\l) ; and 30, 50, 70 DAS in cotton (0n1 and 1n0 mg\l). The HBR treatments significantly (P 0n05 and P 0n01) increased grain yields in wheat, rice and mustard, pod yields in groundnut, tuber yields in potato and seed cotton yields, over control. The extent of yield improvement due to HBR was influenced by crop species, concentration of HBR, plant growth stage at application and frequency of application.

KS91WGRC14 (Reg. no. GP-343, PI 560335) is a durum wheat (Triticum turgidum L. var. durum Desf.) germplasm line homozygous for T1BL-1RS wheat-rye (Secale cereale L.) chromosome translocation, developed cooperatively by the Kansas Agricultural Experiment Station, the Wheat Genetics Resource Center, Kansas State University, USDA-ARS, and the Technical University of Munich. It was released by the Kansas Agricultural Experiment Station and the Wheat Genetics Resource Center, Kansas State University, as a germplasm in February 1992. KS91WGRC14 is a BQFj-derived line from the cross 'Cando'*2/'Veery'. Cando is a durum wheat cultivar, and Veeiy is a bread wheat cultivar carrying a T1BL-1RS wheat-rye chromosome translocation. KS91WGRC14 is the bulked, selfed progeny of a BC,F 2 plant that had 2n = 28 chromosomes and was homozygous for T1BL-1RS, based on C-banding analysis (1). KS91WGRC14 is resistant to cultures of the stem rust fungus Puccinia graminis Pers.: Pers. that are avirulent to the gene Sr31 located on IRS. It is resistant to cultures of the powdery mildew fungus (Erysiphe graminis DC. f. sp. tritici Em. Marchal) that are avirulent to the gene Pm8 located on IRS. KS91WGRC14 also produces polyacrylamide gel electrophoretic bands coded by the secalin locus on IRS (2).

Photoperiod insensitivity plays a significant role in ensuring wide adaptability of genotypes across environments. The effect of photoperiod in groundnut (Arachis hypogaea L.) is manifested in post-flowering development including partitioning. The partitioning of assimilates, as measured by harvest index (HI), has the greatest effect on pod yield. The F1 progenies (excluding reciprocals) and their parents from a six-parent diallel cross were studied to estimate combining ability for biomass and HI under short (SD)-and long (LD)-day conditions, and to identify good combiners with high biomass and HI for use in breeding programmes. The experiment was conducted for three seasons in a split plot design with two photoperiods as main plots and 21 genotypes as subplots. The two photoperiod treatments were SD defined as normal-day light period and LD defined as normal-day light period extended by 4 h using incandescent lamps. The multi-environment analogue of Griffing's Method 2 -Model 1 was modified to analyse data for combining ability. While biomass was controlled by both GCA and SCA effects, HI was predominantly controlled by GCA effects. GCA and SCA effects for biomass and HI interacted with environments (six factorial combinations of photoperiods and seasons). SCA effects remained insensitive to variation in photoperiod both for biomass and HI. However, GCA effects for HI were sensitive to photoperiod. V6 (ICG 2405) was a good general combiner for both biomass and HI across environments. None of the crosses showed positive and significant SCA effects for both biomass and HI. Photoperiod influenced the sensitivity of GCA effects of V2 (ICGV 86694) and V6 for HI. However, the difference between SCA effects of V2 x V6 was not significant. The results of this study emphasise the need for future experiments with random genotypes over a range of photoperiods.

Photoperiod insensitivity plays an important role in the adaptation of peanut (Arachis hypogaea L.) genotypes across environments. However, little is known of its genetic control. The objective of this study was to determine the combining ability of response to photoperiod in peanut. The Ft progenies from a six-parent diallel cross excluding reciprocals were studied together with their parents for response to photoperiod under short and long day conditions in the field for three seasons. The experiment was conducted in a split plot design with photoperiod as main plots and genotype as subplots. The response to photoperiod (Dst) was computed as the difference in harvest index (adjusted pod weight/adjusted biomass) between short and long day treatments. The mean square for response to photoperiod was highly significant for parents and their crosses. Season by cross interaction was the only significant interaction effect. The response to photoperiod was mainly associated with general combining ability variance. ICG 2405 and ICGV 86031 were good general combiners for insensitivity to photoperiod. All crosses of sensitive × sensitive and sensitive × insensitive parents were sensitive to photoperiod. However, in several cases, this response was not consistent across seasons and resulted in a significant season × cross interaction. The F1 between insensitive parents was insensitive to photoperiod in the three seasons tested. A comparison of Ft response with parents and midparent value of crosses between photoperiod sensitive and insensitive parents suggested additive gene action in some crosses and partial dominance to dominance in others. Cr OP IMPROVEMENT PROGRAMS in International Agicultural Research Centers distribute their improved germplasm worldwide. Very often, this germplasm is selected in relatively few test environments. How this material will perform outside of those environments remains a dilemma to breeders until the materials are actually tested. Among other factors, insensitivity to photoperiod plays a significant role in ensuring wide adaptability of these genotypes. Photoperiod has little influence on time to flowering in peanut but affects its reproductive development in many ways by influencing the processes that occur mainly after flowering. Plants grown under short days (SD), in spite of fewer flowers per plant than under long days (LD), produce more pods (Wynne et al., 1973; Wynne and Emery, 1974; Ketring, 1979) due to increased reproductive efficiency and rate of development (Emery et al., 1981; Emery, 1983). Traits affected photoperiod include number of pegs, peg growth, number of pods, pod weight, and seed weight. These traits and their rates of development are altered by greater

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