نشریه به زراعی نهال و بذر
سال بیست و هشتم شماره 2 (1391)

In canola (Brassica napus L.)، such as in most plant species، drought stress affects sink and source relationship as well as photosynthates assimilation، hence reduces seed yield. To evaluate the effect of supplemental irrigation on seed yield and yield components of canola cultivars، an experiment was conducted in 2004–2007 growing seasons at Agricultural Research Station of Gonbad، Iran. The experiment was arranged as factorial in randomized complete block design with three replications. Experimental factors included four irrigation levels (1-without irrigation، 2-irrigation in flowering stage، 3-irrigation in seed filling stage and 4-irrigation in flowering + seed filling stages)، and three canola cultivars (Hyola401، RGS003 and Option500). Combined analysis of variance showed that the effect of year was significant on all studied traits. Mean of pod number plant-1 in without irrigation، irrigation in flowering، irrigation in seed filling and irrigation in flowering + seed filling stages was 150، 145، 163 and 143 pods in 2004-05، 85، 113، 104 and 108 pods in 2005-06، and 73، 95، 95 and 106 pods in 2006-07 growing seasons، respectively. The number of sunny hours during seed formation was a determinant factor of seed production. Mean seed number pod-1 in the first، second and third growing seasons was 15. 1، 21. 6 and 13. 4 seed، respectively. In different growing seasons، the effect of irrigation on seed yield was different، and depended on rainfall at irrigation time. Mean of seed yield in without irrigation، irrigation in flowering، irrigation in seed filling and irrigation in flowering + seed filling treatments was 3283، 3520، 3709 and 3890 kg ha-1 in 2004-05، 3093، 3339، 3047 and 3922 kg ha-1 in 2005-06، and 2802، 2494، 2687 and 2804 kg ha-1 in 2006-07 growing seasons، respectively. Hyola401 had higher seed number pod-1، higher seed weight and the highest seed yield. Mean of seed yield of Hyola401، RGS003 and Option 500 cultivars was 3984، 3552 and 3266 kg ha-1 in 2004-05، 4035، 3109 and 2908 kg ha-1 in 2005-06، and 4093، 2500 and 1497 kg ha-1 in 2006-07 growing seasons، respectively. Results of this study showed that RGS003 is a suitable cultivar to be grown side by side of Hyola401 in Gonbad region of Iran.

Determination of planting spacing for castor (Ricinus communis L.) is very important for obtaining optimum seed yield. This experiment was conducted to study the effects of inter and intra row spacings on some agronomic traits of red castor using split-plot arrangments in randomized complete block design with four replications in 2006 at the Kabotarabad Agriculture Research Station of Isfahan. Main plots were three inter row spacings (55, 75 and 95 cm) and sub-plots were three intra row spacings (20, 30 and 40 cm). Results showed that with increasing inter row spacing, physiological maturity was enhanced. Inter row and intra row spacings had significant effect on plant height, stem diameter and plant dry matter. By increasing plant density, plant height and plant dry matter increased and stem diameter decreased. Inter row spacing significantly affected on number of candles plant-1, number of candles m-2, candle length, 1000 seed weight, seed yield and harvest index. Inter row spacing had no significant effect on number of seed candle-1. Intra row spacing had no significant effect on number of seed candle-1 and 1000 seed weight. By increasing plant density, seed yield increased. Seed yield variation had similar trend to number of candles m-2, candle length, number of seed candle-1 and harvest index. However, variation in trend of seed yield was reversed to the number of candle plant-1 and 1000 seed weight. The highest seed yield (1423 Kg ha-1) was obtained in 55 cm inter row and 20 cm intra row spacings (91 thousand plant ha-1).

To determine the optimum planting rows ratio of female and male parents of KSC704 for hybrid seed production، two separate experiments were conducted in two years (2008 and 2009) in two regions of Kerman province (Orzoiyeh and Bardsir). In each region four planting ratios were evaluated in randomized complete block design with three replications. Planting rows ratios were different Female: Male ratios as follows: 1) common planting ratio (4:1) with four female rows and one male rows in which planting area of female parent was 80%; 2) high density planting ratio (4:2) with four female rows and two male rows on the same furrow in which planting area of female was %80، 3) high density planting ratio (4:1) with four female rows and one male row in which planting area of female was %100، and 4) common planting ratio (4:2) with four female rows and two male rows that planting area of female was 67%. Results showed that in Orzoiyeh region، high density planting ratio (4:1) had the lowest seed yield (1300 kg ha-1)، number of seed per ear، number of row per ear، number of seed per row and the highest cob (%) than the others. There were not significant differences between other treatments in seed yield. Common planting ratio (4:2)، high density planting ratio (4:2) and common planting ratio (4:1) had 2300، 2600 and 2640 kg ha-1 of seed، respectively. In Bardsir، the highest and lowest seed yield obtained from common planting ratio (4:2) with 1850 kg ha-1 and high density planting ratio (4:1) with 990 kg ha-1، respectively. Therefore، planting ratio (4:2)، high density planting ratio (4:2) and common planting ratio (4:1) for Orzoiyeh and common planting ratio (4:2) for Bardsir are recommended for KSC704 hybrid seed production.

To study the effect of harvest in different growth stages on quantity and quality of forage of amaranth varieties a field experiment was carried-out as factorial arrangement in randomized complete block design with three replication in two successive growing seasons (2006 and 2007) in Karaj، Iran. Experimental factors included: four amaranth varieties; Ultra، Kharkof، Kharkofsky and Unknown، and two harvest stages; flowering and after seed set. For forage yield of amaranth varieties، samples were taken from determined area in each plot. For quality assessment of treatments، standard samples were prepared. Results showed that amaranths variaties significantly (P < 0. 01) differed for fresh and forage yields. The highest fresh (86400 kg ha-1) and dry (13320 kg ha-1) forage yields belonged to Ultra. Combined analysis of variance revealed that effects of year and interaction of variety × harvest stage were significant (P < 0. 01) on fresh and dry forage yields. Amaranth varieties significantly (P < 0. 01) differed for crude protein content which varied from 7. 75% to 22. 2%. There were highly significant negative relationship between dry matter digestibility (DMD) and acid detergent fiber (ADF) (r = -0. 874**) and organic matter digestibility (OMD) (r = -0. 911**). The estimated means of DMD، OMD and DOMD (Dry organic matter digestibility) were 71. 1%، 67. 6% and 58. 8%، respectively. Ultra harvested in flowering stage had the highest profit (12880000 IRR). The estimated marginal rate of return of substitution of this treatment with other tretments was 96%. Therefore، Ultra with harvest in flowering stage was identified as suitable treatment.

To analyse growth and variation in trend of some traits of potato a field experiment was carried out in 2003 and 2004 at field research station of Seed and Plant Improvement Institute، Karaj، Iran. A split plot arrangement in randomized complete block design with three replications was used. Planting dates at five levels; 08 April، 24 April، 09 May، 25 May and 09 June were assigned to main-plots and three potato cultivars were randomized in sub-plots. Combined analysis of variancse revealed significant differences among planting dates and potato cultivars for most of the studied traits. Response of potato cultivars to planting dates was different considering the slopes of variation in trends of different traits. Therefore، the observed response are specific to each cultivar. Planting date significantly affected yield and yield components of cv. Agria and variation in trend of traits differed with planting dates. Variation in trend of tuber dry matter (%) and yield showed that both were at maximum level when accumulated growing degree days reached 1000 ºCd after flowering. Variation in tuber growth rate، tuber relative growth rate and tuber yield in different planting dates indicated that there were in agreement، and these indices and tuber yield changed in the same direction in different planting dates. Tuber growth rate varied from 1. 2-1. 5 g m-2 ºCd-1 and the maximum tuber relative growth rate was 0. 125 g g-1 ºCd. It was concluded that the third (09 May) and fifth (09 June) planting dates are suitable for cv. Agria in Karaj region.

Effect of three different irrigation methods on dry matter (%)، emergence (%)، water productivity، yield and some of agronomic traits of four Iranian onion cultivars were studied. The experiment was conducted in 2005 and 2006 growing seasons as strip plot arrangements in randomized complete block design with three replications in Agricultural and Natural Resources Research Station of Neyshabour. Three irrigation methods (drip، furrow and basin) were assigned as vertical plots and four long day onion cultivars (Azarshahr Red، Kashan White، Neyshabour White، Neyshabour Red) were randomized in horizontal plots. Results showed that drip irrigation method increased bulb yield of onion. Irrigation × cultivar interaction effect showed that furrow irrigation improved bulb yield in Kasahn White cultivar by 37% in comparison to basin system. Average yield of Kashan White cultivar in drip irrigation was 30% more than that of basin system. Water productivity in drip irrigation was more than furrow and basin irrigation methods by 28% and 52%، respectively. Mean bulb yield in drip irrigation was 7. 2% less than furrow irrigation and 27% more than basin irrigation.

To evaluate terminal drought tolerance in promising lines of spring rapeseed، using stress tolerance indices، this research was conducted in 2008-09 and 2009-2010 growing seasons in Safiabad Agricultural Research Center، Dezfoul، Iran. Eleven promising lines of spring rapeseed as well as Hyola401 (check) were evaluated in two separate field experiments using randomized complete block design with three replications in non-stress and terminal drought stress conditions. Results revealed that L5 and L4 were more tolerant than other lines using Stress Susceptibility Index (SSI) and Tolerance Index (TOL). However، Stress Tolerance Index (STI) and Geometric Mean Productivity identified Hyola401 and L1 line as genotypes with higher yield in both non-stress and drought stress conditions. Considering all drought tolerance indices، Hyola401 and L1 were suitable and adapted genotypes in terminal drought stress conditions. Study of correlation coefficients between seed yield in non-stress and terminal drought stress conditions and STI، GMP and MP showed that these indices are suitable for identification of terminal drought tolerant promising lines of spring rapeseed.

To evaluate the effect of irrigation intervals and different mulches on some traits of gladiolus cv. Rose Superme، an experiment was carried out as factorial arrangement in randomized complete block design with three replicutions in 2007-2010 growing seasons at Varamin Agricultural Research Center، Varamin، Iran. Experimental factors included: three levels of irrigation intervals; 7، 10 and 15 days and five mulches; no mulch، white plastic، wheat straw، pine dry leaves and black plastic. Plant height، spike length، floret number، flower diameter، corm diameter، corm and cormels weight were measured and recorded. Results showed that irrigation interval × mulch interaction effect was hightly significant (P < 0. 01) on floret number، corm and cormels weight، and cormel number. Growing season also significantly (P<0. 01) affected all traits except corm diameter. In conclusion، irrigation at 10 days interval with black plastic mulch can improve quantity and quality of gladiolus production.

Olive is slow growing plant and its propagation takes long time. To overcome such a constraint، a study was carried-out to investigate the possibility of propagation of olive trees by cutting-grafts during rooting. Four experimental factors included; timing of graft at two levels (before rooting and after rooting)، grafting type at two levels (inverted T and splice)، rootstock at two levels (Gorgan B and Shengeh)، and scion source at three levels (Fishomi، Shirazy and Dezful). The experiment was conducted as factorial arrangement in randomized complete block design with four replications. Results showed that timing of graft and type of graft had significant effect on grafts survival. However، rootstock and scion source had no significant effect on the survival of grafts. Grafting after rooting improved grafts survival by 40%. Inverted T graft increased grafts survival by 30% while grafts survival in splice graft type was 22%. Timing of graft also significantly affected the duration required for transplanting of grafted cuttings. The duration was longer for grafted cuttings after rooting. In conclusion، inverted T graft on rooted cuttings are more suitable for transplanting in green-house.

Karim as a new line (HAMAM-4: T. AEST/SPRW''S''//CA8055/3/BACANORA86 ICW92-0477-1AP-1AP-4AP-1AP-0AP) was evaluated at Gachsaran agricultural research station in 2004-2005. It was selected for its high grain yield (3975 kg ha-1) and included in advance yield trial in Gachsaran، Khoramabad، Gonbad، Moghan and Ilam field stations in next growing season. Average yield of this line and check (cv. Koohdasht) in these stations were 3762 and 3416 kg ha-1، respectively. Karim had also desirable agronomic traits. Therefore، this line along with 17 promising lines were studied in three successive growing seasons (2006-2009) in uniform regional wheat yield trial in Gachsaran، Khoramabad، Gonbad and Moghan field stations. Average grain yield for new cultivar was 3310 kg ha-1 which was significantly higher as compared to check. New cultivar had 338 kg ha-1 (13. 7%) yield superiority to check during 2004-2009 across all field stations. Considering grain yield stability parameter this line had the highest rank with least standard deviation and small within location coefficient of variation. New cultivar showed resistance to important wheat diseases such as yellow rust، leaf rust، common bunt، dwarf bunt and powdery mildew. It has good quality properties in addition to earliness، optimum plant height and high 1000 grain weight. Overall، due to its optimum grain yield، grain yield stability، desirable agronomic traits and quality، Karim was released by Agricultural Research، Education and Extension Organization in 2011.

Khorram was primarily received as an introduction barley for low rainfall area- cold winter (LRA-CW) with the pedigree of Sfa02/3/RM1508/Pro//W12269/4/Hml-02 ArabiAbiad//ER/ApmICB92-0926-0AP-2AP-0AP from International Center for Agricultural Research in the Dry Areas in the 2002-2003 cropping season. Khorram cultivar was tested in the preliminary, advance yield trial and uniform regional yield trial in 2003-2004, 2004-2005 and 2005-2008 in Gachsaran, Koohdasht, Moghan and Gonbad research field stations. Results showed that it yieled 18.06% more than check (cv. Izeh). In addition to high grain yield, Khorram possess desirable agronomic characteristics such as high 1000 grain weight (TGW), high protein content in comparison to check (10.8% vs. 9.4%), acceptable level of resistance to the important barley diseases such as scald and powdery mildew. Khorram was officially released in September 2011 for semi- tropical rainfed areas of Iran