Seed and Plant
Year:2001 | Volume:17 | Issue:3|Papers Count:12

In the present investigation in vitro propagation of GF677 (Hybrid of almond x peach) rootstock was studied. Explants were isolated from apical and lateral buds early April. Plant materials were then sterilized using Hg Cl2 (0.1%) for 6 minutes. The culture media MS, 1/2 MS and modified Knop (with some changes in microelements) were used in experiments. The best shoot proliferation achieved on modified Knop medium containing 2% sucrose, 1mgll BA, without NAA (0.0). In this medium about 5 shoots per test tube were produced and there were significant difference between hormone concentrates at 0 1% level. The conditions of growth chamber was 16-h light period and a 24/26oC day/night temperature regime. Light intensity was 2500-3000 lux and air humidity was 45%. In rooting stage, use of LS medium containing 0.3 mg/l IBA , 1.6 mg/l thiamin and 7 days darkness period, gave the best results of rooting, up to 80% . Propagated plants via tissue culture were transferred to the soil consisting of 40% peat and 60 % sand mixture, or Jiffy blocks, but Jiffy blocks gave better results.

To determine virulence factors in the population of stem rust, several wheat leaf samples infected with Puccinia graminis f.sp. tritici were collected from different areas of Iran during 1996-1997. After purification and spore multiplication, Avirulence/Virulence formula of each isolate was determined in the greenhouse by inoculating them on 44 stem rust near isogenic lines. In another experiment, 20 wheat genotypes were also inoculated by spores of different isolates to evaluate their resistance to each isolate. Twenty different pathotypes were identified in the present study. All isolates were virulent on genes Sr9a, 9d, 9g, 11, 12, 14, 17, 19, 20, 21, 34, while gene Sr27 was resistant to all isolates. Isolate collected from Khorramabad, being virulent on 37 genes, and two isolates from Ahwaz and Busher, being virulent on 22 genes, were the most and the least aggressive isolates, respectively. Wheat genotypes, were classified into 3 groups based on their infection types. Group 1, including Atrak, Attila, Vee/Nac, N-75-2, N-75-4, S-75-14, S-75-19, S-75-4, S-75-16. S-75-2 and S-75-5 were resistant to all or majority of the isolates, group2, including lines N-75-3 , S-75-3 and Bolani (susceptible cheek) were susceptible to all or majority of the isolates, and group 3 which had different infection types to different isolates.

To study the effect of gluten of some wheat cultivars with different electrophoretic patterns on baking quality, two groups of bread wheat (Triticum aestivum), one with glutenin subunits 5+ 10 located on the Glu-D1 locus and the other with glutenin subunits 2+12 located on the same locus were selected. With regard to other subunits, the first group rating (using the Payne method) was suprior to the second group. Flour of Sardari wheat was used as the base flour. It has glutenin subunits 2+12 on the Glu-D1 locus. Gluten was extracted by washing method and were dried up. Gluten powder of the two groups was added to base flour at three levels 1%, 2% and 4% and the farinograph test pf dough and baking quality of "Lavash" bread were compared. Gluten of the first group had better effect on farinograph characteristics especially at 4% level. The final grade of taste panel of the "Lavash" breads evaluated by panel members showed that the gluten of the first group had more positive effect on baking quality than the gluten of the second group.

Fusarium wilt of lettuce caused by the fungus Fusarium oxysporum f.sp. lactucum is a destructive disease of lettuce in fields of Tehran province. A glasshouse experiment was conducted to evaluate resistance and susceptibility of 20 lettuce cultivars obtained from, Denmark, Italy, England, USA and Iran to an aggressive isolate of the pathogen. The Index of percentage of seed germination, number of healthy plants, fresh and dry weight of shoots and dry weight of roots were used for cultivar evaluation. Results indicated that Salinas and Grand Rapids were the most resisitant cultivars base on the mentioned index (P<0.05). In the field experiment nine cultivars were planted in soil with 30% infection during the previous year. A Randomized Complete Block Design with four replications was used. Plants were inoculated around the roots at the two leaf stage with spore suspension of the pathogen isolate. Results indicated that local cultivars curl Ahwazi and Esfahani with no infection were resistant. Black Shahre-Ray and King Crown with 18.42% and 26.2% of infection respectively, showed an intermediate reaction to the pathogen.

Effect of wheat plant density on rate of cereal sawfly infestation was studied in the experimental field of Seed and Plant Improvement Institute in Karaj during 1996 and 1997 cropping seasons. The experiment was conducted in Randomized Complete Block Design with 4 replication and 5 treatments. The treatments were five seed rates of 130, 150, 170, 190 and 210 kgha-1. The developmental stages of the pest and the host were monitored throughout the experiment. After maturation of larva and in the beginning of diapause stage, the experimental field was harvested. The percentage of infestation was determined for each treatment by counting the number of infested and uninfested stems. The percentage of barren spikes, grain yield and 1000 kernel weight were also determined. The data of two years were analysed according to Duncan's Multiple Range Test. The analysis of variance revealed significant differences among the treatments in infestation by cereal sawfly, grain yield and 1000 kerenal weight, but no significant difference was found in barren spikes, and rate of infestation increased by incerease in plant density. Treatment 130 kgha-1 of seed with 4.13% of infestation was the least infested treatment in companson with the other treatments. However, treatments 190, 170, and 210 kgha-1 with 9.40, 9.25 and 8.71% infestation, respectively, were the most infested treatments. In spite of low percentage of infestation in 130 kgha-1 seed rate, it is not recommended because of low grain yield in the treatment.

To study the effects of plant density and source limitation on grain yield, yield components and dry matter and nitrogen remobilization in corn (Zea mays L.), a field experiment was conducted at Seed and Plant Improvement Institute in 1998. A strip plot design based on randomaized complete blocks with 4 replications was used. In this study maize hybrids (KSC704 and KSC711) were sown in vertical plots. Density (65, 70, 75, 80, 85, 90 thousand plant ha-1) and topping levels, T1 (control) and T2 (Removing tassel and all leaves above the ear) were assigned as factorial to horizontal plots. Results revealed that toppng at two weeks after anthesis did not have any adverse effect on grain yield. Therefore, a considerable quantity of forage could be harvested without any reduction in grain yield. The highest yield of green fodder (5.45 tha-1) was obtained from 90 thousand plant ha-1. Although topping caused an increase in 1000 kernel weight by 7 percent compared to control, but there was no significant difference in their grain yield. Remobilization of dry matter and nitrogen from different parts of th shoot (leaves and stem) to the grain responded differently and among them stem contributed more. Maximum remobilization of dry matter from stem (58%) was recorded in 80 thousand . plant ha-1 which had significantand positive correlation with grain yield.

In order to select high yielding cultivars with desirable fruit quality, in this experiment 12 nectarine cultivars, were evaluated in a Randomized Complete block design with 3 replications, in the Kaboutarabad Agricultural Research Station, Isfahan for a 9 years period. Different traits of the cultivars such as vegetative characters, yield and qualitative characters where studied during the period of experiment. In each year simple analysis, and at the end of experiment combined analysis of varince was done on the data. The combined ANOV A results showed that year and cultivar had significant effects on yield and vegetative characters of trees. In means comparison with DMRT method, cultivar Independence with 133178 kgha-1 had the highest yield and cultivar Sunking had the highest vegetative growth among the cultivars. The results also showed that from different points of view such as adaptability, vegetative characteristics, and quantitative and qualitative characters, cultivars Independence, Nectard 6, Sunking, Sungold, Sefide Mashhad and Kuota were perior to the other cultivars. Therefore these cultivars can be recommended as suitable cultivars for Isfahan areas.

Short-term yield trials are the methods for selection of high yielding cultivars that conducted over a range of environments. In multi years and/or multi locational trials, GE interaction may be ignored and selection may have been done just based on mean yield. Different stability analysis methods have been introduced for determination of stable genotypes. The objectives of this study are to determine rank-correlation coefficients among several stability statistics in order to compare their efficiency in studying GE interaction in short-term trials. Three sets of maize hybrids were evaluated in the short-tern yield trials. Set 1 (T1) included 7 early-maturing hybrids grown in 6 environments, set 2 (T2) included 9 very early-maturing hybrids grown in 6 environments, and set 3 (T3) included 14 late and medium-maturing hybrids grown in 5 environments. The rank-correlation coefficients among bi' CVi and S2xi were high and significant. The rank-correlation coefficient between Wi and δi2 was 1 in all of the sets which according to other researchers' results, use one of them preferably δi2, is recommended. Also high rank-correlation coefficients were found among δi2, S2di and Si2 High and consistent rank-correlation coefficients between YSi and RSM with mean grain yield indicated that the use of simultaneous selection criteria result the selection of stable and high yielding hybrids.

The present research was conducted at Maragheh Research Station on 4 commercial bread wheat cultivars (Sardari, Sabalan, Azar and Ghermezghen) as recurrent parents, and 4 resistant lines as donor parents to transfer the resistance to Tilletia laevis Kiihn to the commercial bread wheat cultivars during 1994-2001. In this study two back crosses were used for transferring of resistance. F1 populations were artificialy inoculated with teliospores of a virulent isolate of Tilletia laevis, and resistant plants were selected. Back cross breeding method was used to transfer common bunt resistance to the commercial bread wheat cultivars. Selfing the second back cross generation, coupled with 3 years of selection of resistant progenies identical to the original parents under artificial infections, prodouced some resistant lines such as Sabalan*2/Kal-Blo"s", Sardari*2/Kal-Blo"s" Sardar*2/4/Ald"s"/Pima77/3/CMH24A.630/Bui"s"//Ch74a.630 to Introduce to farmers for planting.

Cultivation of improved cultivars resultes in destruction of plant landraces, and their generations are gradually destroying. In the present study, samples of lentillandraces were collected from different regions of Fars province included: Baladeh Kazeroon, Firozzabad, Abadeh, Shahr Mian, Sedeh, Eghlid, Fasa, Neiriz, Jaffarabad, Ghias abab, Darab, Sarhad Chahar Dangeh, Dasht Risi, Deh Siahi, Jamalabad, Ghanat Ebrahim, Sarchahun, Ardekan, Rostagh Darab, Babamaidan, Ghalehbeigi Fahlian, Khomzar, Golgoon, Ghaemieh, Eslamabad and Noorabad. Collected samples were cultivated in non- replicated single row plots of 2 m long and different characteristics including flowering period, 1000 seed weight, seed/pod, pod length, seed emergence percent, days to maturity, lowest pod height, plant height, leaflet size and pod number were recorded. A stepwise regression method was used for determination of effective parameters in yield. The results indicated that nearly 0.745(R2) of changes in yield are related to three characters including number of pod, size of leaflet and 1000 seed weight. Path analysis showed that direct effect of leaflet size on yield by 0.33 was more than the other characters.