ITEMS FROM INDIA

BHARATHIAR UNIVERSITY

Cytogenetic and Plant Breeding Laboratory, Department of Botany, Coimbatore - 641 046, India.

Genetics, breeding, and induced-mutation studies in wheat and triticale.

V.R.K. Reddy, P. Viswanathan, and S. Arumugam.

Leaf rust-resistance genes (Lr19, Lr24, Lr26, and Lr28); stem rust-resistance genes (Sr25, Sr26, Sr27, and Sr31); and the stripe rust-resistance gene (Yr9) were transferred from wheat stocks and addition lines to the Indian wheat cultivars HD 2009 and HD 2380 after 2-5 backcrosses and through homoeologous recombination (using homozygous recessive ph ph mutant). Selection was made at both BC₂F₅ and BC₅F₅ generations. Early generation selection was found to be better for obtaining superior lines. The lines were tested for yield performance under rust-free conditions. No yield depression effects were noticed in the lines. The presence of rust-resistance genes in an Indian wheat background was confirmed by selecting for the following morphological markers: awnlessness, lax spike, club tip, waxy color, and red grain. That dominant genes controlled rust resistance in the constituted lines also was confirmed by studying the inheritance in F₁, F₂, and BC₁ hybrids derived from a cross between an Indian wheat and the universally susceptible cultivar Agro Local. Significant increases in nuclear DNA, total free phenol, tannin, soluble protein, and peroxidase activity were noticed in the constituted lines.

Ten agronomically desirable mutants were isolated in durum wheat, bread wheat, and triticale using gamma rays, EMS, or a combination of both. Agronomic mutants performed better than the parents in both the M₃ and M₄ generations. Slow-rusting of the resistant mutants was confirmed by the parameters of incubation period, latent period, CDL, AUDPC, and TS. The genetics of mutants for plant height indicate that dwarf mutants (dwarf I and dwarf II) in the durum wheat Jairaj are controlled by a single recessive gene. However, the two are nonallelic and complement each other. The two plant-height mutants in hexaploid wheat (dwarf I and dwarf II) are nonallelic, though each is controlled by single recessive genes.

Three plant-height mutants in triticale, double dwarf, dwarf, and semidwarf, are controlled by a single recessive gene. The semidwarf mutant was dominant over the dwarf and double dwarf, whereas the dwarf mutant was dominant to the double dwarf. An early-flowering mutant in triticale was controlled by two recessive gene. Grain mutants (bold and plump) in triticale were each controlled by a single recessive gene. A leaf rust mutant in the bread wheat WH 147 was controlled by one dominant and one recessive gene.

Incorporation of specific rust-resistance genes in wheat and their confirmation through biochemical and molecular markers.

S. Dhamodaran and V.R.K. Reddy.

Four NILs for each of the leaf rust-resistance genes Lr9, Lr19, and Lr24 were developed by incorporating the Ae. umbellulata-derived leaf rust-resistance gene Lr9, and the leaf rust-resistance genes Lr19 and Lr24 from Ag. elongatum into the four rust-suspectable, Indian wheat cultivars LOK-1, HUW234, J28, and K68 through a backcross breeding program. The endopeptidase null allele Ep-D1c is closely linked to Lr19. The presence of Lr19 in the four NILs was confirmed. The leaf rust-resistant NIL with Lr19 was crossed with the leaf rust-susceptible wheat cultivar Agra Local and the F₂ plants were evaluated for endopeptidase polymorphism. All the F₂ plants that expressed Lr19 and the endopeptidase allele Ep-D1d-D1D were resistant.

We are presently trying to confirm the presence of leaf rust-resistance genes Lr9 and Lr24 in the NILs through RAPD/STS markers obtained from the Swiss Federal Research Group for Agroecology and Agricultures, which showed polymorphism between the NILs for leaf rust-resistance genes Lr9 and Lr24.

Publications.

Reddy VRK, Viswanathan P, Asir R, and Arumugam S. 1996. Effect of variation in rye chromosome composition on chlorophyll mutations in triticale. Adv Plant Sci 9(1):51-53

Reddy VRK, Damodaran S, Asir R, Viswanathan P, and Arumugam S. 1996. Development of disease rust resistance in hexaploid wheat - An overview. In: Plant Breeding Advances and In-vitro culture (Siddiqui BA and Khan S eds). CBS Publishers, New Delhi, India. pp. 179-194.

HIMACHAL PRADESH KRISHI VISHVAVIDYALAYA

Department of Plant Breeding and Genetics, Palampur - 176 062 (H.P.), India.

Surbhi HPW 89 -- a new high-yielding and rust-resistant wheat cultivar for Himachal Pradesh.

Satish C. Sharma, D.L. Sharma, G.S. Sethi, K.S. Thakur, and A.K. Basandrai.

Surbhi HPW 89 (pedigree: Intermedio Rodi/HD 2248) is a new, high-yielding, wheat cultivar with a high degree of resistance to both yellow and brown rusts that has been recommended for cultivation in the low and mid-hill areas (500-1,800 m elevation) of the state under rainfed and irrigated conditions. The cultivar will replace Sonalika and HS 2380 and provide an alternative to the cultivar HS 240. Because Sonalika (the predominantly grown wheat cultivar) and HD 2380 have become highly susceptible to yellow and brown rusts, immediate replacement was needed.

HPW 89 is a semidwarf wheat with dark-green, waxy foliage, and good tillering ability with stiff straw and white glumes. The grains are bold, white-amber, and semihard. The cultivar had significantly higher grain yields than the checks HD 2380 and Sonalika, under both rainfed and irrigated conditions in 1993-94, and irrigated conditions in 1992-93. HPW 89 had a 13.1-15.9 % increase in grain yield over HD 2380 and a 15.1-35.7 % over Sonalika in coordinated trials during these years. However, it is statistically similar in grain yield to the cultivar HS 240. In Himachal Pradesh, HPW 89 was 10.8 and 62.1 % higher in grain yield than HD 2380 and Sonalika, respectively, under rainfed conditions. In irrigated conditions, HPW 89 had 7 and 26.4 % increases in grain yield over HD 2380 and Sonalika, respectively (Table 1).

Table 1. Performance of' wheat cultivar HPW 89 (Surbhi) under timely-sown conditions in Himachal Pradesh (H.P.).

Surbhi (HPW 89) has shown a high degree of resistance to both stripe and leaf rusts under natural and artificial epiphytotic conditions than the best check variety HS 240, which is susceptible (40 MS (7.3) to 25S (14.2)) to leaf rust under artificial conditions (Table 2). Therefore, this new cultivar will provide the necessary disease resistance in addition to the next-best cultivar HS 240.

Table 2. A summary of rust scores and probable resistance genes of the wheat HPW 89 in comparison to the check cultivars.

¹ Rated in the south, under artificial epiphytotic conditions.
² Rated in the north.

HPW 89 has higher tolerance to Karnal bunt (5.7 %) than the checks HS 240 (11.5 %), HD 2380 (20.0 %), and Sonalika (12.0 %). This cultivar also has immunity to FHB (0), compared with the checks HS 240 (11 %), HD 2380 (32 %), and Sonalika (11 %).

A survey of stripe and leaf rust diseases made by the Zonal Wheat Monitoring Team during 1996-97 indicted that the prevalence and severity of stripe rust were very high in the Kullu and Kangra valleys, particularly on Sonalika (80-100S), VL 616 (60-80S), HS 240 (60S), HS 277 (60S), and HPW 42 (10S). Similarly, leaf rust incidence was high on the newly released cultivars HS 295 (60S), and Sonalika, and HD 2380. However, HPW 89 has been found to be resistant to both stripe and leaf rust fungi.

Surbhi HPW 89 has a 1,000-kernel weight of 49.5 g, compared to 36 g for HS 240. HPW 89 has a mean protein content of 78.6 kg/hl. Flowering in 130 days, HPW 89 is earlier than HS 240 (140 days) and, therefore, has a longer grain-filling period than HS 240. In addition, farmers do not favor the cultivation of HS 240, because its late flowering and maturity expose it to natural hazards such as hail and bird damage.

HPW 89 responds to fertilizer application and was superior to HS 240 at all levels of fertilizer application. In agronomic trials, HPW 89 produced the highest mean grain yields in the Northern Hill zone (48.3 g/ha) and was superior to both check cultivars under early or late sowing. Comparable yields were obtained under timely and late planting.

Table 3. Grain yields (Qx/ha) from on-farm trials of HPW 89 versus HS 240 in timely-sown rainfed and irrigated conditions conducted during 1994-95 in Himachal Pradesh. Numbers in parentheses under means indicate the number of trials for each mean.

Zone/Station	Rainfed		Irrigated		Comments
	WPW 89	HS 240	HPW 89	HS 240
Zone I. Submontane, low hill, subtropical, elevation 500-650 m.
District Bilaspur
Research Station, Berthin	24.00	16.00	-	-	HPW 89 preferred. Maturity days: HPW 89 = 138, HS 240 = 144.
District Una
DDA, Una	-	-	29.00	30.00	Both cultivars preferred.
HPKV, RSS, Akrot	-	-	32.00	30.00	Both cultivars preferred.
KVK, Una	-	-	32.25	36.25
District Sirmaur
HPKV, RRS, Dhaulakuan	25.00	25.00	32.00	25.00	Both cultivars preferred. HPW 89 preferred in irrigated conditions.
District Hamirpur
KVK, Hamirpur	30.75	27.00	-	-
Mean of Zone I	26.58 (3)	22.67 (3)	31.31 (4)	30.31 (4)
Zone II. Mid-hills, subhumid, elevation 650-1,800 m.
District Mandi
DDA. Kamdi	33.75	32.50	54.50	40.00	HPW 89 preferred.
Research Station, Sundernagar	33.30	31.20	-	-
District Kullu
DDA, Kullu	-	-	43.75	22.50	HPW 89 preferred.
HPKV, RRS, Bajaura	20.61	19.39	33.80	32.50	HPW 89 preferred for maturity and grain size.
KVK, Bajaura	31.40	28.50	-	-
District Kangra
Research Station, Malan	-	-	33.30	41.60	HPW 89 preferred. Early flowering.
Directorate of Extension	-	-	35.00	32.50
Horticulture	-	-	36.50	40.00
	-	-	20.00	25.00
	-	-	28.75	35.00
	-	-	30.00	37.50
DDA, Palampur	45.00	23.00	31.50	24.00
Research Station, Kangra	-	-	50.00	60.00
Mean of Zone II	32.81 (5)	26.92 (5)	35.50 (12)	34.34 (12)
Overall mean	30.47	25.32	34.45	33.32
Zones I & II, weighted	(8)	(8)	(16)	(16)

The results of on-farm trials conduced in Himachal Pradesh indicated the superiority of HP 89 in grain yield (30.5 Qx/ha) over the best check cultivar HS 240. Particularly under rainfed conditions, HP 89 had a 20.3 % increase over HS 240 for the combined Zones I and II (Table 3). However, under irrigated conditions, the grain yields were statistically similar.

Additional cultivar release - Aradhana (HPW 42).

Aradhana (HPW 42), developed by university scientists S.C. Sharma, D.L. Sharma, G.S. Sethi, and K.S. Thakur, was released by the Himachal Pradesh State Seed Sub-Committee for cultivation under late-sown conditions in low and hid-hill areas of the state.

INDIAN AGRICULTURAL RESEARCH INSTITUTE

Division of Genetics, New Delhi - 110 012, India.

R.N. Sawhney.

Accessing and exploiting rust resistance genes of alien origin in wheat breeding.

Recent studies at several locations on the series of leaf rust-resistance genes Lr1-Lr34 to individual races of leaf rust in the seedling stage, and mixture of most important races in adult plants have identified Lr9, Lr19, Lr21, Lr24, Lr25, Lr26, Lr28, Lr29, and Lr32 as genes conferring a moderate to high degree of resistance effective at all stages of plant growth. In addition, Lr22a and Lr34, which confer resistance only at the adult plant stage, were identified. All these resistance genes except Lr34 are of alien origin and are, for the most part, unexploited in India (Sawhney 1994, 1995). However, the wheat-rye translocation T1BL-1RS, with resistance genes Lr26/Sr31/Yr9, has been extensively used in breeding cultivars both in India and throughout the world. The leaf rust resistance conferred by Lr26 in the translocation has now become ineffective due to evolution of the fungus. Leaf rust resistance in the recently released variety Kanchan (DL 803-3, Sawhney et al. 1995, 1996) is possibly due to Lr34, because the genes Lr23 and Lr26 in the T1BL-1RS translocation are ineffective. Lr34 is associated with durable resistance to leaf rust. Nevertheless, broadening the genetic base of resistance with genes derived from species related to T. aestivum is likely to remain effective for a longer period of time. Resistance genes from alien species are mostly available in agronomically poorly adapted backgrounds but can be utilized effectively after crossing with genetically enhanced germplasm. Recovery of desirable genotypes in a breeding program is likely to be efficient.

A backcross-breeding program has developed several prebreeding stocks with yields higher, or comparable to, those of the recurrent parent wheats, Kalyansona (Sawhney and Sharma 1996) and Sonalika (Sawhney, unpublished data) with no undesirable effects. These materials encourage wheat breeders to use resistance genes transferred from alien species to tailor a new generation of cultivars with genetic diversity and high levels of resistance. Our efforts in this direction have already achieved significant results. The wheat cultivar Vaishali (DL784-3), with resistance genes Lr24/Sr24 from Ag. elongatum was released in 1993. Vaishali is for cultivation in eastern India under irrigated and high-input conditions. The use of the Ag. elongatum-derived resistance gene in the development of Vaishali was the first attempt in India (Sawhney and Joshi 1996). Vaishali is preferred by the farmers of eastern India, particularly in high humidity areas that are prone to leaf rust epidemics. This cultivar is perhaps the only wheat in the zone that continues to maintain a high degree of resistance to leaf and stem rusts. Another high-yielding short-duration wheat DL788-2, with Lr24/Sr24 resistance was officially released in August, 1996, for late planting in the Central Zone of India.

Exploitation of Aegilops tauschii var. meyeri Lr21/Sr21.

Kalyansona backcross derivatives, with resistance genes Lr21/Sr21, when used in different cross combinations have produced promising cultivars: DL1012-2, DL1013-6, DL1017-1, DL1063-1, and DL1079-1. These wheats, when tested as seedlings with diagnostic virulences, identified specific genes (Lr21/Sr21) that were transferred for resistance to leaf and stem rusts. Successful use of Lr21/Sr21 resistance leading to the development of cultivars is the first attempt in the world. DL1013-6 has been identified as possessing a unique combination of Lr21 and Lr23 genes. Like DL1013-6, the other varieties also are likely to possess genes in addition to Lr21. McIntosh et al. (1995) reported that Lr2l has potential for use in breeding, but remained unexploited.

Exploitation of Agropyron elongatum (Lr24/Sr24) resistances.

In addition to DL784-3 (Vaishali) and DL788-2, a number of other wheats developed from different cross combinations involving Kalyansona backcross derivatives have Lr24/Sr24. These wheats include DL975-1, DL975-2, DL976-1, DL944-1, DL995-2, DL997-4, DL997-7, DL1010- 2, DL1023-1, DL1070-1, and DL1107-1. All these wheats are likely to possess resistance in addition to that contributed by the specific donor genes Lr24/Sr24. Because there is no virulence to Lr24 in India at present, identification of additional leaf rust resistance in these wheats is difficult. Some of these wheats are in the advanced stage of testing in the All India Coordinated Programme, high-yielding, and resistant to rusts.

Newly described adult plant resistance genes with potential for durability.

Leaf rust resistance in lines with Lr35 (source: RL 534 `Ae. speltoides/T. monococcum') and Lr37 (source: Ae. ventricosa) was recently determined. Lr35, operative only in adult plants and nonspecific, is likely to have durable resistance to leaf rust, but its durability can be confirmed only after the gene is introduced in commercial cultivars and grown extensively (Sawhney et at. 1994). Lr37, effective in adult plants (Sawhney, unpublished), is reported to be linked with stem rust-resistance gene Sr38 and stripe rust-resistance gene Yr17. These genes have been extensively used in the Australian breeding program where rust resistance controlled by these genes is still effective. A number of wheats with these resistance genes are being released (McIntosh et al. 1995). This source of resistance may play a significant role in breeding a high degree of resistance that could possibly be durable.

References.

McIntosh RA, Wellings CR, and Park RF. 1995. Wheat Rusts - An Atlas of Resistance Genes. CSIRO, Australia. pp. 200.

Sawhney RN. 1994. Breeding for durable resistance to wheat rusts. IARI Monograph. Publication and Information Directorate, Dr. K.S. Krishnan Marg, New Delhi 110 012. pp. 52.

Sawhney RN, Sharma JB, and Sharma DN. 1994. Non-specific adult plant resistance to leaf rust with potential for durability. Cereal Rusts and Powdery Mildews Bulletin 22 (part 2). pp. 9-13.

Sawhney RN. 1995. Genetics of wheat rust interaction. Plant Breed Rev (Jenick J ed). 13:293-343.

Sawhney RN, Sharma JB, Sharma DN, Chowdhary HB, Mehta H, and Singh SS. 1995. Kanchan - A high yielding rust resistant wheat variety for sustainable production under diverse agroclimatic conditions. Seed Tech News Bull, Indian Soc Seed Tech 25(4):1-3.

Sawhney RN and Joshi BC. 1996. Genetic research as the valid base of strategies for breeding rust resistant wheats. Genetica 97:243-254.

Sawhney RN and Sharma JB. 1996. Introgression of diverse genes for resistance to rusts into an improved wheat variety, Kalyansona. Genetica 97:255-261.

Sawhney RN, Singh SS, Choudhary HB, Mehta H, Sharma JB, and Sharma DN. 1996. Kanchan, a high yielding wheat for the Central India. Indian Farming 46(7):61-63.

INDIAN AGRICULTURAL RESEARCH INSTITUTE

IARI Regional Station, Pusa, Bihar, Dist. Samastipur - 848 125, India.

Two wheat cultivars identified for the NEP zone.

M.P. Jha, B.P. Sinha, K.M.P. Singh, and A.K. Sinha.

Two wheat cultivars, HP 1744 and HP 1761, developed at the IARI Regional Centre, Pusa, have been identified by the 35th All India What Research Workers Workshop in 1966.

HP 1744 (pedigree: Ciano/Parula/Chilero/Garuda) is an early-maturing (110 days), semidwarf cultivar suitable for irrigated, late sowing. The average height of HP 1744 is 80 cm. HP 1744 is resistant to lodging and leaf rust. A genetic analysis of HP 1744 indicated that Lr1, Lr13, Lr23, Lr26, Lr34, Sr2, Sr8, Sr11, Sr31, and Yr9 are present in this cultivar. Resistance gene Lr34 provides adult-plant resistance. HP 1744 also is resistant to foliar blight.

HP 1761 (pedigree: RL6010/6*Inia//3*Kauz) is suitable for timely sown, highly fertile, irrigated conditions. This cultivar will not lodge and may yield over 6 T/ha. HP 1761 has resistance gene Lr9, providing near immunity to leaf rust. HP 1761 also is moderately resistant to the leaf blight fungus. Postanthesis heat tolerance with quick grain filling may allow HP 1761 to escape grain shrivelling during periods of dry, westerly winds in mid-March. This cultivar may replace UP 262, UP 206, and K 8804, which have become susceptible to the leaf rust and leaf blight fungi and may compete with WH 542 (a Kauz line), a promising new variety for the NWP zone.

go to next document