Wheat physiology.

P.D. Jamieson.

The wheat simulation model Sirius has now been validated for several sites and a variety of irrigation and N-fertilizer treatments in the U.K. and New Zealand and accurately predicts biomass accumulation, water use, grain yield, N uptake, and grain N in most circumstances. A description of the model is soon to be published (Jamieson et al. 1996c). The model will be used to assess regional variation of wheat yield in Europe and to assess the likely impact of climate change on the performance of crops for a selection of sites in New Zealand. A simple model of grain filling, based on the concept that the harvest index (HI) changes linearly with time, has been tested with data from a variety of crops in New Zealand and the U.K. (Moot et al. 1996). The analysis showed that, in most circumstances, HI changed by about 1 % per day during grain filling, so that variations in grain yield were associated mostly with the amount of biomass present at flowering and the duration of grain filling. However, the model broke down in low N fertility conditions. Analysis of the variation of MDD baking quality data versus weather over a period of years showed that high quality in spring wheat was associated with low rainfall and high temperatures during grain filling (Salinger et al. 1995) and that cool temperatures and rain during this period decreased quality. This suggests that N management is critical when these latter conditions occur.

Publications.

Jamieson PD and Wilson DR. 1993. Physiological and agronomic limits to wheat yield and quality. Agron Soc NZ Special Pub No. 8. pp. 25-32.

Salinger MJ, Jamieson PD, and Johnstone JV. 1995. Climate variability and wheat baking quality. NZ J Crop Hort Sci 23:289-298.

Moot DJ, Jamieson PD, Henderson AL, Ford MA, and Porter JR. 1996. Rate of change of harvest index during grain filling in wheat. J Agric Sci, Camb (In Press).

Jamieson PD, Brooking IR, and Porter JR. 1995. How temperature and daylength determine flowering time in spring wheat. Proc Agron Soc NZ 25:(In press).

Jamieson PD, Brooking IR, and Porter JR. 1996a. A new model of spring wheat phenological response to temperature and daylength. Proc 8th Aus Agron Conf, Brisbane. Pp. 337-340.

Jamieson PD, Martin RJ, Francis GS, and Porter JR. 1996b. Analysing wheat biomass and grain yield response to drought using AFRCWHEAT2. Proc 8th Aus Agron Conf, Brisbane. p. 669.

Jamieson PD, Semenov MA, Brooking IR, and Francis GS. 1996c. Sirius: a mechanistic model of wheat response to environmental variation. Field Crops Res (In press).

ITEMS FROM PAKISTAN


REGIONAL AGRICULTURAL RESEARCH INSTITUTE

Agronomic Research Station, Bahawalpur, Pakistan.

M.S. Cheema and M. Hussain.

Wheat production.

Although an increase in wheat production in Pakistan has been recorded in recent years, its production has not kept pace with actual need. Wheat production was 15.1 mmt in the year 1993-94, reached a level of 16.7 mmt in the year 1994-95, but the total requirements far exceed actual production. Consequently, the government of Pakistan has planned to import 2.0 mmt in the year 1995-96 to meet the consumption requirements. Wheat demands of Afghanistan also are met from Pakistan, and there is an increased use within Pakistan, because of a population growth rate of 3.1 % annually. Wheat is the staple food crop of Pakistan and is the cheapest source of food grain. The present fixed price of domestic wheat by the government is Rs. 165 ($6 US) per 40 kg (1 maund), whereas the cost of imported wheat is about Rs. 231.50 ($8.50 US) per 40 kg. Growing wheat is not attractive economically, because of high inputs and low net return compared to other food crops. Big farmers are reluctant to grow wheat and prefer to grow other crops like sunflower, maize, vegetables, and fodder crops, or leave their fields fallow until the next (Kharif) season. However, small farmers will grow wheat for their household consumption.

Breeding of wheat genotypes in Pakistan during 1994-95.

Wheat is grown in all the four provinces of Pakistan, but the Punjab province is the main contributor with 70 % of the total production. In the Punjab province, wheat is planted at normal (November) and late (December-January) times. Late sowing is needed because cotton and rice are harvested late in the season. So, genotypes are specified for normal or late planting. In addition, cultivars also are bred for irrigated and rainfed areas.

Cultivars for the rainfed areas of the Punjab province include `Pothwar-94', pedigree `Ures/BOW `S'', a good-tillering cultivar that is resistant to leaf rust and has good grain quality and `Kohsar-95', pedigree `PSN `S'/BOW `S'', a high-yielding cultivar resistant to leaf and yellow rusts.

Cultivars for the irrigated areas of the Punjab province include `Parwaz-94', pedigree `V.5648/PRL `S'', a short duration cultivar, resistant to leaf rust, with good grain quality, and recommended for late planting; `SR-95', pedigree `S.A.42/V.1299', is recommended for normal sowing, is tolerant to leaf and yellow rusts, and has good grain quality; `Shahkar-95', pedigree `VL 711//F 3.71/TRM', is a leaf and yellow rust-resistant cultivar with good grain quality and recommended for late sowing; and `Bahawalpur-95', pedigree `AU/UP 301//GLL/SX/3/PEW `S'/4/MAI `S'/MAYA `S'//PEW', is a high-yielding cultivar resistant to leaf rust, tolerant to lodging, with good grain-filling ability in hot seasons, and good for chapati making.


ITEMS FROM ROMANIA

I.C.C.P.T. - RESEARCH INSTITUTE FOR CEREALS AND INDUSTRIAL CROPS

Fundulea, 8264, jud. Calarasi, Romania.

Association of Fusarium scab resistance with the 1D gliadin locus.

N.N. Saulescu, Mariana Ittu, Gh. Ittu, and P. Mustatea.

The AUDPC and the relative weight of artificially inoculated spikes (% of noninoculated controls) were determined in 1995 for over 100 near-homozygous recombinant lines, obtained through an SSD-like procedure from the cross `Sincron/F1054W2.' Lines also were characterized for several marker loci, such as Rht-1(Gai), Rht8, Gli-1B, and Gli-1D.

A large variation was found for both AUDPC and relative weight among the recombinant lines. AUDPC varied from 165 to 1,150, and the relative weight varied from 21 to 82 %.

The mean value of the AUDPC for Gli-1D2 lines (514.5) was significantly lower than mean value for Gli-1D4 lines (650.1). Accordingly, the average relative weight of inoculated spikes for all Gli-1D2 lines (40.3 %) was significantly higher than that for the Gli-1D4 lines (34.3 %). In 1994, a significant difference was found for relative weight, but not for the AUDPC.

Our results suggest that a major QTL for Fusarium scab resistance is located on chromosome lD, close to the Gli-1D locus. No association was found between Fusarium scab resistance and the other loci studied (Rht-1(Gai), Rht-8, or Gli-1B), in any of the years.

Further research plans include characterization of the recombinant lines for other marker loci, with the hope of finding other possible associations, and investigating other sets of homozygous recombinant lines, to find out how general the reported association is.

Superiority of Triticale over other small grains in the hilly regions of Romania.

Gh. Ittu, N.N. Saulescu, and Mariana Ittu.

A comparison was made between the average yields of the main released Triticale, barley, rye, and wheat cultivars in yield trials conducted during the last 3 years at five to eight locations in the hilly region. Triticale cultivars outyielded barley by 1.96 t/ha, rye by 1.39 t/ha, and wheat by 0.54 t/ha, on average, in 19, 13, and 25 trials, respectively. When the average yields of the five highest yielding entries from these trials with new lines of triticale, barley, rye, and wheat were compared, triticale still had yield increases of 1.70 t/ha over barley, 0.98 t/ha over rye, and 0.41 t/ha over wheat.

These results suggest that the higher level of tolerance to aluminum toxicity and the superior resistance to powdery mildew, rusts, and Septoria tritici of Triticale are important in conferring yield superiority over barley and wheat. Better resistance to lodging could explain the superiority over rye.

With the newly released cultivars, Colina and Plai, Triticale proves to be a better choice among the small grains for feed grain production on the acid soils of the hilly regions. However, considerable progress must be achieved before it becomes competitive for breadmaking.


S.C.A. - AGRICULTURAL RESEARCH STATION

Turda, jud. Cluj, Romania.

TURDA 95, a new winter wheat cultivar.

V. Botezan, V. Moldovan, and Maria Moldovan.

`Turda 95' was released in 1995. The cultivar was obtained by individual selection (the pedigree method) from the cross `L99 I 1-2/T6-80-86.

TURDA 95 belongs to T. aestivum ssp. vulgare var. erythrospermum, having white, awned spikes and red grains. Turda 95 is a high-yielding semidwarf (95 cm), intermediate between the control cultivars Fundulea 4 and Ariesan. This cultivar is of medium maturity, and the vegetative period is equal to that of Fundulea 4 and 2-4 days longer than that of Ariesan.

The cultivar Turda 95 has good resistance to winterkill, drought, lodging, and shattering. Good resistance to yellow rust, stem rust, mildew, Septoria, and Fusarium also are found in the cultivar. However, Turda 95 is susceptible to leaf rust.

Turda 95 is characterized by high yield potential. The average in the ecological network (51 trials) was 68 q/ha, and in another 24 trials, it produced upwards of 70 q/ha, with a maximum yield of 103.7 q/ha.

The regression coefficients of Turda 95 yields, calculated in relation to the yields of Fundulea 4 and Ariesan, were subunitary (b = 0.78 and 0.87, respectively), which denotes the tendency of Turda 95 to yield better in unfavorable environments.

Turda 95 is characterized by good quality, which is reflected by grains harder than those of both Fundulea 4 and Flamura 85, and by high protein and gluten contents both in the grain and flour. According to milling and baking indices, Turda 95 is classified among the good quality wheats.

The hard red winter wheat Turda 95 combines high yield potential with quality and some agronomic characters responsible for yield stability. Thus, it represents real progress in wheat breeding in Romania.