Corm Size Research Articles

Effects of Corm Size, Organic Fertilizers, Fe-EDTA and Zn-EDTA Foliar Application on Nitrogen and Phosphorus Uptake of Saffron (<i>Crocus sativus</i> L.) in a Calcareous Soil under Greenhouse Conditions

A greenhouse research experiment was conducted. The experiment was arranged in factorial layout based on a completely randomized design. The mother corm size (0.1-4 g, 4.1-8 g and 8-12 g), organic fertilizers (cattle manure 15 t ha-1, vermicompost 10 t ha-1,chamomilecompost 10 t ha-1 and control) and micronutrients (Fe-EDTA and Zn-EDTA) in two levels (foliar application and no application) were assigned as the first, second and third experimental factors, respectively. Based on the results, with increasing mother corm size, formation of small corms (0.1-4 g) decreased, whereas the percentage of medium (4.1-8 g) or large size (more than 8 g) corms increased. The highest corm yield was observed when cattle manure was applied. Moreover, foliar application increased daughter corm yield in medium and larger size corms. Phosphorus and nitrogen concentration in daughter corms increased with increasing the size of mother corms. Organic fertilizers significantly increased phosphorus and nitrogen concentration in all size of corms: phosphorus content in large daughter corms increased five times on account of cattle manure application. Proper nutrient management during the first year of saffron propagation could improve corm number than rather corm weight.

How irrigation rounds and mother corm size control saffron yield, quality, daughter corms behavior and phosphorus uptake

In saffron (Crocus sativus L.) production, whether corms or stigma, irrigation management and mother corms size play a key role in nutrients uptake, daughter corms formation and stigma yield. Herein the effects of irrigation rounds and mother corm size on daughter corms behavior, phosphorus uptake, stigma yield and quality were evaluated as a two-year field experiment based on a randomized complete blocks design arranged in factorial-split with three replicates. In this study, 15 main plots [irrigation rounds at five levels (no irrigation during growing season, summer irrigation in August, summer irrigation+October irrigation, summer irrigation+October irrigation+November irrigation and summer irrigation+October irrigation+November irrigation+April irrigation)×mother corms’ size at three levels (≤5g or small-sized, 5.1–10g or middle-sized and >10g or large-sized)] and two sub-plots (the first and second year) were considered. From the results, the maximum flower number (101.9 flowers per m2) and dried stigma yield (373.8mgm−2) were obtained when large-sized (>10g) mother corms were planted. Irrespective of mother corm size, the maximum flower number and dried stigma yield were observed when four irrigation rounds were performed. Nevertheless, the maximum crocin and picrocrocin content were obtained under no irrigation conditions. In both years, large-sized daughter corms weight and phosphorus acquisition efficiency increased with increasing mother corms size. Moreover, phosphorus content in saffron parts and phosphorus acquisition efficiency significantly increased with increasing irrigation rounds. Overall, although four irrigation rounds are highly recommended, applying at least two rounds (in summer and before flowering in October) under limited water conditions is unavoidable.

NPK Levels and Application Methods on Productivity of Amorphophallus muelleri Blume in Intercropping System

Underground corm of Amorphophallus muelleri Blume contained glucomannan, a raw material widely used in beverage, food and medicinal industries. In Indonesia, A. muelleri is grown under intercropping system, however, average corm production was considered low. The low productivity could be related to the low input of chemical fertilizers. Therefore, the effects of NPK fertilizers and methods of application on A. muelleri productivity were evaluated in the present study for intercropping system. Two experiments were conducted at Leuwikopo Experimental Farm, Bogor, Indonesia from 2010-2012 under canopy of coffee trees. First experiment was conducted using four levels of N, P, and K applications, i.e., N:P2O5:K2O at the rate 0:0:0, 100:60:80, 125:60:100 and 150:60:120 kg ha-1. In second experiment, N:P2O5:K2O fertilizers at the rate of 100:60:80 were applied by conventional (solid) and liquefied. Results of first experiment showed that application of N, P and K at rate of 100 kg, 60 kg, and 80 kg ha-1 produced fresh corm weight 636.3±91.7 g per plant or increased by 63% higher than control. However, higher rate of NPK application did not increase corm yield, possibly due to the occurrence of leaf discoloration. Higher rates of NPK also delayed harvest time 1 to 2 weeks compared with control and caused wide variation of corm size. Thus, excess application of NPK should be avoided for high productivity of A. muelleri. Second experiment showed that there was no significant different among methods of application on fresh corm weight, i.e., 413 g and 396 g from conventional and liquefied applications, respectively. These experiments conclude that application of NPK is important to enhance A. muelleri production in intercropping system.

NPK Levels and Application Methods on Productivity of Amorphophallus muelleri Blume in Intercropping System

Underground corm of Amorphophallus muelleri Blume contained glucomannan, a raw material widely used in beverage, food and medicinal industries. In Indonesia, A. muelleri is grown under intercropping system, however, average corm production was considered low. The low productivity could be related to the low input of chemical fertilizers. Therefore, the effects of NPK fertilizers and methods of application on A. muelleri productivity were evaluated in the present study for intercropping system. Two experiments were conducted at Leuwikopo Experimental Farm, Bogor, Indonesia from 2010-2012 under canopy of coffee trees. First experiment was conducted using four levels of N, P, and K applications, i.e., N:P2O5:K2O at the rate 0:0:0, 100:60:80, 125:60:100 and 150:60:120 kg ha-1. In second experiment, N:P2O5:K2O fertilizers at the rate of 100:60:80 were applied by conventional (solid) and liquefied. Results of first experiment showed that application of N, P and K at rate of 100 kg, 60 kg, and 80 kg ha-1 produced fresh corm weight 636.3±91.7 g per plant or increased by 63% higher than control. However, higher rate of NPK application did not increase corm yield, possibly due to the occurrence of leaf discoloration. Higher rates of NPK also delayed harvest time 1 to 2 weeks compared with control and caused wide variation of corm size. Thus, excess application of NPK should be avoided for high productivity of A. muelleri. Second experiment showed that there was no significant different among methods of application on fresh corm weight, i.e., 413 g and 396 g from conventional and liquefied applications, respectively. These experiments conclude that application of NPK is important to enhance A. muelleri production in intercropping system.

English

Gladiolus is an important estimated 8th in the world cut flower trade’s cut flower grown throughout the world for its elegant attractive spikes of different hues and good keeping quality. The commercial cultivation of Gladiolus is based on natural multiplication of corms and cormels. However, multiplication rate of corms and cormels is slow and the conventional method of propagation is insufficient to meet the demand of planting material and eventually affect the final cost of corms. A number of improved conventional techniques including division of the corms, removal of leaf and flower spikes, use of standard corm size, and mechanical removal of sprouts can increase the multiplication rate of corms and cormels. These improved conventional methods of propagation are insufficient to meet the demand of planting materials. In vitro techniques are applicable for the propagation of corm producing species. These techniques are adopted at commercial level in order to fulfill supply gap of huge demand. A number of in vitro protocols have been developed for regeneration of Gladiolus plantlets using different media by using various explants sources of the plant. However, literature is rather scanty on in vitro cormel formation and acclimatization of in vitro propagules. Key words: Corms, cormels, galdiolus, propagation.

Effect of growth substances on growth, flowering and corm production in gladiolus (Gladiolus grandiflorus) cv White Prosperity under Bay Island conditions

Field experiment was conducted for two consecutive seasons during November-April of the years 2011-12 and 2012-13 in the Division of Horticulture and Forestry, Central Island Agricultural Research Institute, Port Blair to study the effect of plant growth regulators on gladiolus (Gladiolus grandiflorus Hort.) cv. White Prosperity. The results revealed that various growth, flowering and corm characters were significantly affected with the application of different growth regulators at different concentrations. Earliness in corm sprouting was observed by GA3 at 500 ppm (10.6 days) .Maximum number of leaves/plant and plant height was obtained by GA3 at 750 ppm (8.2 and 111.0 cm respectively). More number of shoots per corm was observed by BA at 100 ppm (3.7). In respect of flower characters early spike emergence and maximum duration of the spike was recorded by GA3 at 500 ppm (49.0 days and 17.5 days respectively). Maximum spike length, rachis length and number of florets per spike (79.3 cm, 56.5 cm and 14.7 respectively) were recorded by GA3 at 750 ppm. In respect of corm characters maximum number of corms and cormels per plant was observed in BA 100 ppm (3.4 and 19.3 respectively). Maximum weight of single corm, weight of corms/plant, size of single corm and volume of single corm (77.5 g, 189.1 g, 7.6 cm and 86.3cc respectively) were recorded in GA3 at 750 ppm. Maximum weight of cormels per plant was recorded in BA at 100 ppm (7.1g). Maximum value of propagation co efficient was recorded in GA3 at 750 ppm (386.4%).

Influence of superabsorbent polymer rates on growth of saffron replacement corms

Mother corm size is the most important factor for production of replacement corms, flower, and stigma yield in saffron. In semi-arid regions, water shortage is a deterrent agent for appropriate corm growth of saffron. Therefore, in this experiment the effects of six levels of superabsorbent polymer (SAP) including 0, 10, 20, 30, 40, and 50 kg ha-1 was investigated on growth indices of replacement corms of saffron. For this purpose, an experiment was evaluated at the research farm of the Saffron Research Group, Sarayan Faculty of Agriculture, University of Birjand, Iran, during 2013-2015. Results showed that SAP application did not considerable effect on corm growth indices in the first life cycle of saffron. Nevertheless, consumption of 30-40 kg ha-1 SAP somewhat improved the number and total weight of replacement corms per clone. In the second life cycle of saffron, the positive impact of SAP was clearly observed on the growth of replacement corms. The application of 40 kg ha-1 SAP increased the amount of number of replacement corms per clone by 13%, total weight of replacement corms per clone by 36%, and scale weight of corms per clone by 50% compared with control. In addition, the amount of mean weight of replacement corms and mean number of buds per corm in treatment of application of 40 kg ha-1 SAP were 29 and 27% higher than the control treatment, respectively. SAP application decreased the amount of non-standard (< 8 g) corm production while significantly increased the percentage of corms with standard weight. Overall, the increasing effect of SAP application on corm weight, bud number, and standard corm yield was higher than the number of produced corms per clone. In addition, water-use efficiency in SAP application treatments (6.1 kg standard corm m-3) was more than the control (4.34 kg m-3) treatment. In total, SAP application is an appropriate strategy for production of standard saffron corms in semi-arid regions.

Effect of Plant Growth Regulators on Corm Production and Vase Life in Gladiolus

Influence of plant growth regulator sprays on corm production and post-harvest life of two gladiolus cultivars, Darshan and Dhiraj, was investigated for two consecutive years, 2008-09 and 2009-10. Growth regulators, viz., gibberellic acid (100 and 150ppm), tri-iodo benzoic acid (TIBA) (50 and 100ppm), 2-chloro, 4-pyridyl phenyl urea (CPPU) (2.5 and 5ppm) and brassinosteroid (BR) (5 and 10ppm) were sprayed at the 3rd and 6thleaf stage. Cv. Darshan recorded maximum number of large cormels per plant and cormel weight, while, cv. Dhiraj recorded maximum number of small cormels per plant in treatments of pre-harvest foliar sprays with plant growth regulators. Foliar sprays of BR (10ppm) and GA3 (150ppm) significantly increased number of corms produced per plant, corm size, corm weight, and propagation coefficient. Number of large cormels and total number of cormels per plant were significantly higher in BR (10ppm), followed by TIBA (100ppm). BR (10ppm) and TIBA (100ppm) produced maximum number of small cormels per plant. Weight of cormels per plant was maximum in BR (10ppm) and GA3 (150ppm). Post-harvest studies revealed that cv. Darshan recorded maximum diameter of second fully-opened floret and higher vase-life than cv. Dhiraj with pre-harvest foliar spray of plant growth regulators. Pre-harvest foliar spray of GA3 (150ppm), BR (10ppm) and CPPU (5ppm) induced earliest first-floret opening and recorded maximum value for number-of-floretsopen- at-a-time per spike, diameter of second fully-opened floret, and vase-life. Foliar spray of BR (10ppm) and GA3 (150ppm) at 3rd and 6th leaf stage can be recommended for large-scale multiplication of quality planting material and longer vase-life of flower spikes, respectively, in gladiolus.

Effect of corm size and plant population density on corm yield of Taro (Colocasia Esculenta L.)

A R T I C L E I N F O A B S T R A C T Objective: Taro (Colocasia esculenta L. Schott) is a perennial root crop that belongs to Araceace family. It is widely cultivated as a staple food in Africa, Asia and pacific Islands. Despite its importance, there is limited information on many aspects of the crop. In order to obtain data that can support improved and sustainable taro production, a field trial was conducted to study the effects of corm size and plant population density on the growth and corm yield of taro (variety Boloso-1) was investigated during 2007 cropping season. Methods: The experiment consisted of five-corm size (50, 51-100, 101-150, 151- 200 and 201-250 g) and five levels of planting densities (15037, 29629, 45454, 60606 and 74074 plants/ha) arranged in a factorial randomized complete block design with three replications. Results: The results indicated that corm size had a highly significant (p<0.001) influence on plant height, leaf number, shoot number , leaf area index, corm and cormels number/plant, corm and cormels yield/ ha of taro. All the parameters were increased with increased in corm size. Plant population density exert significant influence (p<0.001) on all the studied parameter except on plant height and number of leaf/plant. The interaction effect of corm size and population density was none significant on all the studied parameters. The highest average corm yield/ha (44.07 t/ha) was achieved at a population of 60,606 plants/ ha using seed corms having 51-100 g. These could be recommended for farmers in production area similar with the study site.

Relationship between nitrogen and phosphorus use efficiency in saffron (Crocus sativus L.) as affected by mother corm size and fertilization

Field experiments were conducted to determine the effects of mother corms size and type of fertilizer on acquisition and use efficiency of nitrogen (N) and phosphorus (P) in Saffron, at Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. The experiment designed as factorial-split with three replicates, 12 main plots [mother corm size (4g and lower, 4.1–8g, 8.1–12 gand over 12g)×fertilization (composted cattle manure 25tha−1, chemical fertilizer (N 300kgha−1 + P 100kgha−1 and control)] and two sub-plots (first and second year). In both years, the larger mother corms (8.1–12g and more) resulted in a greater nitrogen content (gm−2) in daughter corms and the whole plant. In addition, acquisition and use efficiency of (N) and (P) were increased with increasing mother corms size. In both years, (N) and (P) use efficiency in composted cattle manure treatment was significantly higher than that of chemical fertilizer (by 21 and 61%, respectively). There was a positive and significant correlation between (N) use efficiency and (P) use efficiency (R2=0.98**) and between (N) harvest index and (P) harvest index (R2=0.99**).

Varietal assessment and variability studies on gladiolus under south Gujarat conditions

The present investigation was carried out to evaluate the performance of 16 gladiolus (Gladiolus hortulanus) varieties under south Gujarat agro-climatic conditions. Significant differences were observed for all the growth, flowering and yield characters during experimentation. The three years pooled data revealed that maximum plant height (73.04 cm) was recorded in variety Her Majesty. Variety Sancerre recorded maximum leaf area (104.79 cm2) and was found superior with respect to qualitative parameters like floret size (10.47 cm), florets per spike (14.29), rachis length (43.78 cm), spike length (76.86 cm), duration of spike (17.80 days), vase-life (10.31 days) and weight of corms (48.74 g). Early flower spike initiation (52.82 days) and first floret opening (65.36 days) was noted in variety Green Star. Variety Psittacinus Hybrid recorded the maximum number of leaves (9.09) and spikes per plant (2.64). Corm size (7.56 cm) and corms per plant (2.53) was obtained maximum in variety Candyman and Priscilla, respectively. Whereas, maximum weight of cormels per plant (11.10 g) was noted in variety Gunjan. The molecular investigation through RAPD markers revealed the highest genetic similarity (0.824) between the accessions Punjab Dawn and Wine & Roses, whereas, the lowest genetic similarity (0.172) was registered between the accessions Eurovision and Her Majesty.

Effect of Plant Growth Regulators on Yield and Quality in Gladiolus under Bay Island Conditions

Field experiments were conducted for two consecutive seasons during 2011-12 and 2012-13 to study the effect of plant growth regulators on gladiolus cv. Chandini. The results revealed that various growth, flowering and corm characters were significantly affected with the application of different growth regulators at different concentrations. Earliness in corm sprouting, spike emergence and maximum duration of spike was observed in GA3 500ppm. Maximum number of leaves per plant, plant height, maximum spike length, rachis length and number of florets per spike were observed in GA3 750ppm. More number of shoots per corm (3.3) was recorded by Benzyl Adenine (BA) at 75ppm. With respect to corm characters maximum number of corms and cormels per plant were observed in BA 100ppm. Maximum weight of single corm, weight of corms per plant, size of single corm and volume of single corm were recorded in GA3 500ppm. Maximum weight of cormels per plant was recorded in BA 100ppm. Maximum value of propagation coefficient was recorded in GA3 500ppm (318.3%).

Effect of plant density and initial corm size on the corm yield of konjac (Amorphophallus konjac)

The effect on annual konjac corm production of planting heavier corms and increasing plant density was investigated at Pukekohe Research Station, New Zealand. Corm yields were 2.2 times the planted corm weights giving a mean corm weight of 741 g harvested from large corms (325 g) and 334 g from small corms (150 g). The mean corm yield increased 1.5 t ha−1 for every 10 g increase in planted corm weight in the 150–330 g range. Increasing the plant density from 33,330 to 106,670 plants ha−1 had a strong linear effect on corm yield. The total yield of corms and offsets from large planted corms increased by 7.2 t ha−1 for each additional plant m−2 to lift yields from 34.9 t ha−1 to 88.1 t ha−1. For small planted corms, total yields rose from 13.7 t ha−1 to 43.9 t ha−1 giving an increase of 4.1 t ha−1 for each plant m−2 increase. Offset production was 12% of the total corm yield grown from large corms and 20% when grown from small corms with no effect from plant spacing.

Desenvolvimento de gladíolos em função da adubação nitrogenada e diâmetro do cormo

&lt;p&gt; O gladíolo é uma das plantas ornamentais mais cultivadas no Brasil, entretanto poucas são as informações científicas relacionadas à cultura. O objetivo desta pesquisa foi avaliar o efeito da adubação nitrogenada e tamanho do cormo no crescimento e floração de &lt;em&gt;Gladiolus grandiflorus &lt;/em&gt;‘San Remo’. O experimento foi conduzido na área de Jardinocultura da Universidade Federal da Grande Dourados (UFGD) em Dourados – MS. O delineamento experimental utilizado foi inteira­mente casualizado e os tratamentos dispostos em parcelas subdivididas, sendo as parcelas constituídas dos diâmetros dos bulbos (grandes entre 40 e 55 mm; médios entre 20 e 40 mm e pequenos inferior a 10 mm), e as subparcelas de três doses de nitrogênio (30, 50 e 70 kg ha-1), com 10 repetições. Foram avaliados o número de folhas, o comprimento da folha, o início da floração, o número de botões por espiga floral, a durabilidade da flor, a duração da floração e o número de cormilhos. As hastes florais produzidas foram classificadas como Classe III. A adubação nitrogenada foi mais eficiente para o crescimento de cormos de tamanho médio e pequeno, sendo que doses superiores a 50 kg ha -1 promoveram os melhores resultados. Em relação à floração, cormos de tamanho grande e a adubação nitrogenada de 30 kg ha -1 atrasaram seu início. Recomenda-se a utilização de cormos de tamanho médio e adubação nitrogenada de 50 kg ha -1 para o cultivo de &lt;em&gt;Gladiolus grandiflorus &lt;/em&gt;‘San Remo’.&lt;/p&gt;

Vegetative, floral and yield attributes of gladiolus in response to gibberellic acid and corm size

Vegetative, floral and yield attributes of gladiolus in response to gibberellic acid and corm size

Apical dominance in saffron and the involvement of the branching enzymes CCD7 and CCD8 in the control of bud sprouting.

BackgroundIn saffron (Crocus sativus), new corms develop at the base of every shoot developed from the maternal corm, a globular underground storage stem. Since the degree of bud sprouts influences the number and size of new corms, and strigolactones (SLs) suppress growth of pre-formed axillary bud, it was considered appropriate to investigate SL involvement in physiology and molecular biology in saffron. We focused on two of the genes within the SL pathway, CCD7 and CCD8, encoding carotenoid cleavage enzymes required for the production of SLs.ResultsThe CsCCD7 and CsCCD8 genes are the first ones isolated and characterized from a non-grass monocotyledonous plant. CsCCD7 and CsCCD8 expression showed some overlapping, although they were not identical. CsCCD8 was highly expressed in quiescent axillary buds and decapitation dramatically reduced its expression levels, suggesting its involvement in the suppression of axillary bud outgrowth. Furthermore, in vitro experiments showed also the involvement of auxin, cytokinin and jasmonic acid on the sprouting of axillary buds from corms in which the apical bud was removed. In addition, CsCCD8 expression, but not CsCCD7, was higher in the newly developed vascular tissue of axillary buds compared to the vascular tissue of the apical bud.ConclusionsWe showed that production and transport of auxin in saffron corms could act synergistically with SLs to arrest the outgrowth of the axillary buds, similar to the control of above-ground shoot branching. In addition, jasmonic acid seems to play a prominent role in bud dormancy in saffron. While cytokinins from roots promote bud outgrowth. In addition the expression results of CsCCD8 suggest that SLs could positively regulate procambial activity and the development of new vascular tissues connecting leaves with the mother corm.

Planting density and corm size effects on flower yield and quality of cut-freesia (Freesia hybrid) in Ethiopia

Planting density and corm size effects on flower yield and quality of cut-freesia (Freesia hybrid) in Ethiopia

English

Genotypic &times; environment (G &times; E) interactions in 35 indigenous line of elephant foot yam (Amorphophallus paeoniifolius Dennst Nicolson) were evaluated for two consecutive years of 2007 and 2008 under four environments in randomized block design (RBD) for yield, plant height, weight of corm, size of corm, dry matter and starch content. Mean squares deviation due to environment and environment linear variations were highly significant for all the traits. Linear component of genotype &times; environment interaction assumed importance for weight of corm, size of corm and yield. Thus, the prediction of the genotypes in the environments appeared to be feasible for all the characters under study. G &times; E interaction was found to be significant for dry matter and starch content indicating that these quality contributing traits were highly influenced by the change in environment leading to extension of analysis for estimating stability parameters. All traits significantly observed for environment + (genotype &times; environment) interaction confirming the influence of environment and suggesting the existence of considerable variation among genotypes as well as environments. On the basis of all three stability parameters (xi, bi and S2di), the genotype NDA-9 possesses high mean, nearer to unit regression and non-significant low deviation from regression. With respect to yield on the basis of all three adaptability parameters, it is evident that the genotype NDA-9 is stable as it possesses high mean, nearer to unit regression and non-significant low deviation from regression. Whereas the highest yielding genotype NDA-35 showed above average sensitivity and low deviation from regression, this genotype could be considered as a suitable for favorable environmental condition.&nbsp; Key words: Stability analysis, genotypic &times; environment interaction, adaptability, yield, quality traits, elephant foot yam. &nbsp;

Impacts of Treated Wastewater Reuse on Some Soil Properties and Production of Gladiolus communis

Two experiments, one in Open Field (OF) and the other inside a Greenhouse (GH), were conducted at Al-Jubeha Agricultural Research Station –The University of Jordan, to study the effect of Treated Wastewater (TWW) on soil chemical and physical properties. It was also intended to find the effect of TWW on spike quality of gladiolus. Five water treatments were used for both experiments, T1:100% Potable Water (PW); T2:100%TWW; T3:25%PW +75%TWW; T4:50%PW+50%TWW; and T5:75%PW+25%TWW. The design for both experiments was Randomized Complete Block Design (RCBD). The results in both experiments showed high accumulation of salts in soils for all treatments with the highest accumulation values in soil T2. Soil organic matter (OM) and N were reduced after planting for all treatments in the GH treatments, but OM remained almost the same in the OF treatments. There was an increase in Zn, Pb, and Cu microelements in soils for all treatments. Soil physical properties such as aggregate stability was reduced for all treatments significantly after planting by about 40% for the GH treatments, and nonsignificantly by about 3-12% for the OF treatments. Soil water retention curve and pore size distribution did not significantly change after planting for the soil for all treatments in both experiments. Plant properties, from both experiments, were affected by TWW irrigation. Parameters such as: spike length, spike diameter, corm size, number of florets per spike, and the number of cormels per corm were found to be affected by water treatments. It gave the worst quality for plants that irrigated with 100% TWW for both experiments. Based on results obtained from both experiments, it was found that soils were affected negatively by TWW irrigation for their chemical and physical properties. Use of TWW when mixed with some PW for irrigation of non-edible plants such as cut flowers gave better results than using PW alone.

Saffron (Crocus sativus L.): The effect of mother corm size on progeny multiplication, flower and stigma production

The three year study of saffron (Crocus sativus L.) production from 27 mother corm weight grades, investigated mother corm progeny multiplication, corm weight, flower number and fresh stigma yield. Annual production results were pooled into 9 mother corm weight classes (0.5, 1–2, 3–5, 6–10, 11–15, 16–20, 22–30, 34–36, 38–53g), and 5 progeny corm weight grades (<5, 5–10, 10–15, 15–20, >20g). Yearly production equations were fitted for total progeny corm number and weight from the 27 mother corm classes. In year 1, the fitted asymptotic curve showed mother corm weight above 16g had little effect on progeny corm number, but in year 2, a linear relationship showed the production of progeny corms was not constrained by the original mother corm weight, while in year 3, progeny corm number was constrained to an asymptote of 69 corms per original mother corm. We measured large changes in the distribution of progeny corm size over the three generations. For the three respective harvest years mother corms >33g produced 22, 47 and 22% of their progeny corms >10g and of these 6, 30 and 0.4% were >20g. For the three respective harvest years, mother corm weight classes >33g, produced 7, 30 and 69 progeny corms with a weight of 60, 406 and 427g, while the 11–15g mother corm class produced 4.8, 10.3, and 45 progeny corms with a weight of 35, 144 and 356g. Cumulative flowering followed a typical sigmoid curve with the main flowering period for the heavier grades of mother corms finishing after 45 days in the first year and 25–30 days in the two subsequent years. Smaller corms flowered 5–7 days later than the largest corms, while mother corms lighter than 2g produced very few flowers. The mother corm weight classes >33g produced 4, 16 and 48 flowers and 115, 627 and 1905mg of fresh stigma per original corm over the three generations. In contrast the 11–15g mother corm weight class produced 1, 4 and 20 flowers and 29, 171 and 906mg fresh stigma per original corm. We conclude the flower and fresh stigma production is highest in a 3 year management cycle, but if large progeny corms are desired a 2 year management cycle would produce more large progeny corms.