Comparisons of Earlier- and Later-formed Pods of Chickpeas (Cicer arietinum L.)

In chickpeas (Cicer arietinum L.) flowering and pod developmentproceed acropetally. In plants grown under normal field conditionsat Hyderabad, in peninsular India, and at Hissar in north India,at successively apical nodes of the branches there was a declinein pod number per node, weight per pod, seed number per podand/or weight per seed. The percentage of nitrogen in the seedswas the same in earlier and later-formed pods at Hyderabad;at Hissar the later-formed seeds contained a higher percentage.Earlier- and later-formed flowers contained similar numbersof ovules. The decline in seed number and/or weight per seedin the later-formed pods of 28 out of 29 cultivars indicatedthat pod-filling was limited by the supply of assimilates orother nutrients. By contrast, in one exceptionally small-seededcultivar there was no decline in the number or weight of seedsin later-formed pods, indicating that yield was limited by ‘sink’size. Cicer arietinum L., chickpea, flowering, pod development, seed number, seed weight, nitrogen content     

The Influence of Genes ar and n on Senescence in Pisum sativum L.

The effect of genes ar (violet flowers, small hilum) and n (thick,fleshy pod wall) on whole plant in senescence peas was examinedby comparing Ar- with arar and N- with nn plants in segregatingprogenies. Homozygosity for ar or n significantly delayed the time whenthe plants were ready for harvest of their entire seed crop.These genes did not delay either the onset of reproduction orthe onset of apical arrest in the first instance. However, whereasAr- N- plants almost invariably senesced and died as the firstseed crop matured, the majority of arar and/or nn plants entereda period of secondary growth and a further fruiting cycle. Comparedwith Ar- plants, arar plants had over twice as many pods andseeds but individual seeds were 58 per cent lighter and totalseed yield (wt) was 19 per cent less. Pod length was unaffected.Compared with N-plants, nn plants had shorter pods (16 per cent),fewer seeds per pod (21 per cent), smaller seeds (20 per cent)and a lower total seed yield (wt 14 per cent less). It appearsthat ar and n impose a lower metabolic drain per reproductivenode as a consequence of their effects on hilum anatomy andpod morphology, respectively. These mutants disrupt the normalpattern of monocarpic senescence by breaking the coordinationbetween apical arrest and subsequent events. The developingseed crop delimited by the first arrest fails to cause plantdeath, possibly because sink size is less than in normal counterparts. Pisum sativum L, garden pea, senescence, hilum, pod, seed size, genetics     

Density Studies on Lupins. II. Components of Seed Yield

Components of seed yield of cv. Ultra (Lupinus albus L.) andcv. Unicrop (L. angustifolius L.) were measured when grown atthree densities. The low density (10 plants m^–2) Unicropyield (34 g seed per plant) was 1.8 times that of Ultra as ithad more branches, pods and seeds per pod. Ultra seeds (310mg per seed) were heavier than Unicrop seeds (180 mg). The branchingpattern of Ultra was less dependent on plant density, henceat 93 plants m^–2 it gave a higher per plant yield (7.4vs 6.4 g) than Unicrop at lower densities (83 plants m^–2).Density had most influence on pod formation and only small effectson seeds per pod and seed weight. Yield components on the main-steminflorescence were influenced less by density than componentson branch inflorescences. Later formed, higher order generationsof inflorescences were most affected by increased inter- andintra-plant competition. Pod numbers on the main-stem were similarfor both species. Pods formed at higher flower nodes in Unicrop,but the lower flower nodes were less fertile than those in Ultra.Node position of flowers had no influence on seed set in main-stemUnicrop pods, but pods from higher nodes in Ultra formed fewerseeds. Seed weights in Unicrop were similar among main-stemnodes but in Ultra seed weights tended to increase at highernodes. Lupinus spp, lupins, seed yield, planting density     

适宜河北省旱寒区的冬油菜品种的筛选

筛选适宜河北省低平原地区种植的油菜品种,同时实现生态效益和经济效益,为相似气候区油菜品种的种植选择及种植结构的调整提供理论依据。以16个油菜品种为材料,对品种间农艺性状的变化进行方差分析、相关性分析和聚类分析。各品种间分枝部位存在差异,变异系数为61.82%,品种JR5分枝部位最低,14T×38最高;其次差异较为明显的是产量和二次分枝数,变异系数分别为26.69%和24.89%,14T×38产量最高,20SY-13最低。二次分枝数最大和最小的品种分别为20SY-13和天油142。油菜产量与一次分枝数和主花序角果数呈极显著正相关(P<0.01),株高与分枝部位、主花序长度和主花序角果数呈显著正相关关系,一次分枝数与主花序角果数呈显著正相关(P<0.05),二次分枝数与主花序角果数呈极显著负相关。当欧式距离为5时,16个油菜品种可分为五大类。选择株高较高、一次分枝数和主花序角果数较多、二次分枝数较少且可以在当地正常越冬的油菜品种进行种植,可以获得较高水平产量;20SY-13在当地秋季种植应注意安全越冬。     

The Effects of Shading on the Yield Components of Six 'Leafless' Pea Genotypes

The effect of unshaded, 30 and 80 per cent shade conditionson the growth rate and yield composition of six ‘leafless’pea (afaf: stst) genotypes has been determined. No evidencefor a photoassimilate source limitation was found in the unshadedand 30 per cent shade treatments, but 80 per cent shade significantlyreduced the yield and the rate of d. wt and node productionof all the genotypes. Yield development was followed in each environment by determiningthe number of flowering nodes, the number of flowers producedper node, the pod number per node and the seed number per pod.The theoretical maximum for each of these yield components wasdetermined and compared with the actual level realized by theplant. Approximately 50 per cent of the theoretical potentialof each yield component was realized and this appeared to beindependent of the shade treatment. This stepwise reductionin potential yield throughout the development of the plant wassimilar to that reported for conventional pea plants. Pisum sativumL, ‘leafless’ peas, shading, growth rate, yield'components, source limitation     

An Analysis of the Influence of Plant Density on the Growth of Vicia faba: I. THE INFLUENCE OF DENSITY ON THE PATTERN OF DEVELOPMENT

The competitive effects of varying the density on the developmentof Vicia faba have been studied in a series of multifactorialexperiments where the spacing both between and within rows wassimultaneously altered. Over densities ranging from 11 to 67plants per metre² seed production on an area basis tended tobe maximal at 35–45 plants per metre² in the winter typeand at the highest density for the spring type. As the densityincreased the number of pods per plant and the extent of branchingfell progressively but there was no appreciable change in eitherseed size or the number of seeds per pod: thus seed productionwas solely governed by the number of mature pods formed. Thenumber of flowers per plant was more dependent on the numberof inflorescences than on the number of flowers per inflorescence.Increasing the population diminished the number of nodes bearinginflorescences particularly in the upper part of the shoot,while the size of the inflorescence was decreased to a lesserextent. The number of flowers forming mature pods was very small(9–14 per cent.). At the top of the shoot the flowerswere infertile, while above the middle node most of the podsformed were shed while still immature. Thus the primary effectof increasing density was to depress the number of nodes onthe lower half of the stems which produced mature pods. By thetime the flowering stage was reached plant height was alreadycorrelated with density due more to a change in internode lengththan an alteration in the number of differentiated nodes; atmaturity the differences in height were smaller due to the greaternumber of nodes in the widely spaced plants. For a given density,alterations in the distance between rows had little influenceon development. The possible physiological factors responsiblefor the changing pattern of development brought about by varyingdensity are discussed.     

Comparisons of Earlier- and Later-formed Pods of Pigeonpeas (Cajanus cajan (L.) Millsp.)

On branches of indeterminate cultivars of pigeonpea, floweringbegins at the basal nodes and proceeds acropetally; in morphologicallydeterminate cultivars, flowering begins on the apical racemesand proceeds basipetally. In cultivars of both types, withinthe racemes flowering proceeds acropetally. Under normal conditionsmore pods are set from earlier-formed flowers than from later-formedflowers, many of which are shed. Consequently the earlier-formedpods are found at the more basal nodes of racemes, and in indeterminatecultivars at the more basal nodes on the branches. The averageweight of earlier and later-formed pods, collected from thebasal and apical nodes of the racemes or of the branches, wassimilar; so was the number of seeds per pod, the weight perseed and the nitrogen content of the seeds. This pattern differsfrom that found in most herbaceous legumes, where later-formedpods are smaller, and indicates that pigeonpeas set fewer podsthan they are capable of filling. This behaviour may be relatedto the intrinsically perennial nature of pigeonpeas. The comparisonof the weights of earlier- and later-formed pods could providea simple screening procedure for identifying plants with anannual nature among existing cultivars or in breeders' lines. Cajanus cajan (L.) Millsp., pigeonpea, pod development, seed number, seed weight, nitrogen content     

Morphological and Agronomic Traits of a Wild Population and an Improved Cultivar of Common Bean (Phaseolus vulgaris L.)

Through the process of domestication, bean varieties have beenselected from their wild ancestors for various anthropocentrically-importantcharacteristics. In order to compare some agronomic and morphologicaltraits of a wild population and a modern variety (cv. Bayo Mecentral),the following variables were evaluated: growth habit; numberof nodes on the main stem; number of branches and pods per plant;flower and pod colours; stem length; days to initiation of flowering;days to physiological maturity and duration of flowering. Variationin each trait was recorded, particularly in the wild population.The growth habits of the wild population were very diverse andthere were positive and significant correlations between 13pairs of variables, including the number of nodes on the mainstem, pods per plant, days to flowering and duration of flowering,whereas domesticated beans gave only a few significant correlations.The analysis of principal components indicated that the linearcombination of agronomic and morphological variables, involvingthe first three principal components, accounted for 70% of thetotal variability of the data, and the populations were clearlyseparated as two biological entities by the first principalcomponent. This study confirms that the process of domesticationhas acted to reduce variation in a range of characters. Growth; growth habit; Phaseolus vulgaris ; domestication     

Mobilization of Minerals to Developing Seeds of Legumes

The mineral nutrition of fruiting plants of Pisum sativum L.,Lupinus albus L. and Lupinus angustifolius L. is examined insand cultures supplying adequate and balanced amounts of essentialnutrients. Changes in content of specific minerals in leaves,pods, seed coat, and embryo are described. P, N and Zn tendto increase precociously in an organ relative to dry matteraccumulation, other elements more or less parallel with (K,Mn, Cu, Mg and Fe) or significantly behind (Ca and Na) dry weightincrease. Some 60–90 per cent of the N, P and K is lostfrom the leaf, pod and seed coat during senescence, versus 20–60per cent of the Mg, Zn, Mn, Fe and Cu and less than 20 per centof the Na and Ca. Mobilization returns from pods are estimatedto provide 4–39 per cent of the seeds' accumulations ofspecific minerals, compared with 4–27 per cent for testatransfer to the embryo. Endosperm minerals are of only minorsignificance in embryo nutrition. Comparisons of the mineral balance of plant parts of Lupinusspp. with that of stem xylem sap and fruit tip phloem sap supportthe view that leaves and pod are principal recipients of xylem-borneminerals and that export from these organs via phloem is themajor source of minerals to the seeds. Endosperm and embryodiffer substantially in mineral compostition from phloem sap,suggesting that selective uptake occurs from the translocationstream during seed development. Considerable differences are observed between species in mineralcomposition of plant organs and in the effectiveness of transferof specific minerals to the seeds Differences between speciesrelate principally to Ca, Na and certain trace elements.     

Stability of performance of okra as influenced by planting date

Summary Fifteen selected okra genotypes, consisting of six from a pedigree breeding programme and nine established varieties as checks, were evaluated in five different environments for stability of performance. Performance was measured by pod yield per plant, number of days to flowering, final plant height, number of branches per plant, number of pods per plant and edible pod weight. A regression method and a genotype grouping technique were employed in the evaluation. The results showed significant genotype × environment interaction only with respect to number of days to flowering and number of branches per plant. Additive environmental effect was significant for all characters. Line UI 313 was considered stable with respect to pod yield per plant and edible pod weight. One line resulting from the pedigree breeding programme was also considered stable by the genotype-grouping technique.     

Yield components and cultivar, sowing date and density in field beans (Viciafaba)

Delay in sowing the cultivars Ostlers (Viciafaba var. equina) and Herz Freya (V.faba var. minor) beyond late February depressed yield. Densities of at least sixty plants per m² were required to ensure that yield was not limited by sowing rate. Differences in yield in response to changes in density were reflected particularly in changes in numbers of pod-bearing nodes per plant, but also to a lesser extent in numbers of pods per pod-bearing node. The inherently larger seed weight of cv. Ostlers compared with cv. Herz Freya did not confer any yield advantage, differences in number of beans per pod and number of pods per pod-bearing node tending to equalize the yield of the two cultivars. The most stable component of yield throughout was number of beans per pod, and the least stable was number of pod-bearing nodes per plant.     

Periods of Shoot Chilling Sensitivity in Soybean Flower Development, and Compensation in Yield after Chilling

Soybeans [Glycine max (L.) Merr. cv. Ransom] grown at a constant25 °C were placed in a 12-h inductive photoperiod at twoweeks of age. Subgroups were shoot-chilled for one week at aconstant 10 °C during each of the first four weeks of floralinduction. Controls were photoinduced but not chilled. Chillingduring the first week of photoinduction inhibited productionof floral primordia, but did not increase the abscission rateof flowers and pods. Chilling during the second week did notaffect primordium production or abscission rate, but did causea significant increase in numbers of fused and malformed pods.Chilling during the third week caused loss of 77 per cent ofearly flowers and pods by abscission, while fourth week chillingcaused less severe losses by abscission. Inhibition of vegetativegrowth may have been responsible for primordium loss in first-weekplants, while disturbances in the development of flowers wereresponsible for the losses in the other chilling weeks. Althoughchilling during the first and third photoinduction weeks causeda significant reduction in early pod numbers, plants harvestedat 16 weeks of age showed no significant loss in seed yield.Low abscission rates late in pod filling and increased weightof individual seeds compensated for early losses of pods. Thesecompensatory responses to a chilling-induced loss of pods aresimilar to those reported for mechanically depodded soybeans. Glycine max (L.) Merr., soybean, temperature, chilling, floral initiation, anthesis, abscission, yield, compensation     

Interactive effect of cytokinin and potassium on sink-source relationships in Lupinus angustifolius

This study examined whether increased K supply in conjunction with BAPcould increase lupin seed yield and harvest index by enlarging sink volume (podnumber), increasing assimilate and improving assimilate partitioning to filltheadditional pods induced by BAP treatment. Narrow-leafed lupin(Lupinusangustifolius, cv. Danja abs^– mutant) was grown inaglasshouse, in pots containing sandy soil with four K treatments (0, 15, 60 and120 mg K/kg soil). BAP (2 mM) was applied daily toallmain stem flowers throughout the life of each flower from opening to senesced.BAP application did not affect assimilate production (as measured by totalabove-ground biomass), but changed assimilate partitioning. On BAP-treatedplants, there were greater proportions of seed to pod wall dry weight on themain stem but smaller proportions on the branches, and an increased weightratioof seed to pod wall overall which meant more assimilate was used for seedgrowthrather than pod wall growth. BAP increased the number of pods per plant by35% and this more than compensated for the decreases in seeds per podandseed weight. Therefore, there was an increased harvest index (+11%)and seed yield per plant (+13%) in BAP-treated plants. BAP alsoincreased the number of pods with filled seeds (146%) on the main stemand main stem seed K⁺ concentration (from 0.81% to0.87%). Added K increased biomass but only slightly affected assimilatepartitioning. As applied K increased, relatively more assimilate was used forpod wall growth rather than seed growth. Added K increased seed yield per plantby about 14% due to increases in seed weight and the number of pods onthe main stem. Moreover, K⁺ concentration in seeds and shootsincreased with increasing level of applied K. Seed yield was enhanced more byBAP when K was supplied at high levels. Increasing K supply interactedpositively with added BAP by increasing narrow-leaf lupin seed yield andharvestindex through increases in assimilate supply and its partitioning into seeds.     

Regulation of Leaf Senescence by Reproductive Sink Intensity in Cowpea (Vigna unguiculata L. Walp)

The relationship between seed number per pod and senescenceof the leaf in its axil was examined in a determinate cowpea(Vigna unguiculata L. Walp) variety C.779. The seed number perpod was reduced at all fruiting nodes by surgical excision ofpart of the 4-d-old pod. Leaf senescence as measured by lossof leaf area, chlorophyll content and soluble protein was sloweddown in leaves supporting the development of an artificiallyreduced number of seeds. Diminished nitrogen mobilization fromthe leaf could not account for the reduced rate of leaf senescence.The result suggests the involvement of a senescence signal fromthe developing seeds to the leaf in its axil. Development ofthe basal half of the excised pod in the cowpea provides a uniquesystem for manipulating seed number per pod. Senescence, monocarpic, chlorophyll, protein, Vigna unguiculata, cowpea     

Foliar boron applications increase the final number of branches and pods on branches of field-grown soybeans

Our previous work demonstrated that boron (B) supplied to soybeans (Glycine max [L.] Merrill cv `Williams 82') by a stem infusion technique increased the number of pods on branches and led to a significant yield increase. Therefore, research was continued to determine whether soil or foliar applications of B could be used to achieve the same results. Field experiments were completed with both soil and foliar applications of B. Only the foliar applications of B resulted in a significant increase in the number of pods/branch. When split foliar treatments were applied twice during flowering, the total application of 0.56 kilograms of B per hectare was the optimal treatment for increasing pods/branch. In a second field experiment in 1987, soybeans were treated weekly from flowering through podfill with six split foliar applications of aqueous H₃BO₃ solutions so that total applications were either 0, 1.1, or 2.24 kilograms of B per hectare. Foliar applications increased the number of branches/plant at the end of the season and significantly stimulated the formation of pods on branches, with 1.12 kilograms of B per hectare being the optimal treatment for these variables. This rate also tended to increase the number of seeds/plant and seed yield/plant. A duplicate experiment with minor modifications was conducted during the summer of 1988, and again the 1.12 kilograms of B per hectare application rate resulted in significant increases in number of branches at harvest as well as number of pods on branches. The 2.24 kilograms of B per hectare application rate also significantly increased these parameters. Foliar B applications induced increases in leaf B concentration far above the 60 micrograms per gram level that was previously accepted as the upper level of tolerance for soybeans. Since optimal branching and per plant yield parameters were achieved by plants with B leaf concentrations greater than 160 micrograms per gram, the accepted range of soybean tolerance for B must be reconsidered when B is foliarly applied.     

Factors affecting the Abscission of Reproductive Organs in Yellow Lupins (Lupinus luteus L.): I. THE EFFECT OF DIFFERENT PATTERNS OF FLOWER REMOVAL

1. The effect of various patterns of flower removal on pod settingwas investigated in Lupinus luteus L. Four-fifths, three-fifths,or two-fifths of the flowers of the main inflorescence wereremoved according to ten different patterns. 2. All flowers could produce pods but later ones were less efficientin doing so. Developing pods had an abscission-inducing effecton later flowers, which became increasingly effective towardsthe apical part of the inflorescence. More pods were retained when flowers on each consecutive whorlwere arranged in a spiral than when the same number was arrangedvertically. Pod setting was incomplete when the number of flowers per inflorescencewas reduced well below the total number of pods normally present. 3. The number of ovules in consecutive flowers gradually decreasedfrom an average of 5.7 at the base to 4.3 at the top of theinflorescence. The ratio of seeds to ovules fluctuated irregularlybetween 65 and 94 per cent, and did not indicate a general trendin embryo abortion. 4. The growth-rate of pods at the top of the inflorescence wasmuch slower than at the bottom. Vascular differentiation wasalmost absent at the top of the inflorescence when the flowerswere fertilized, and further vascular tissue was produced onlywhen flowers produced pods.     

Effect of Removal of Flower Buds, Open Flowers, Young Pods and Shoot Apex on Growth and Pod Set in Soybean

The complete removal of the reproductive structures once andshoot apices of soybeans (Glycine max L. Merrill) during earlyanthesis but before the rapid seed development stage significantlyincreased flowering and pod set in greenhouse and field grownplants. The treated plants had darker green leaves, shorterstems and petioles and retained their chlorophyll content longerthan control plants. Pod maturation was also delayed. Althoughdecapitation and the removal of reproductive structures increasedthe number of 3- or more-seeded pods in all varieties tested,seed weight per plant was not consistently increased. The possibleinvolvement of endogenous hormones in pod set and multi-loculepod production in soybeans is discussed. Key words: Glycine max (L.) Merr, Reproductive structures, Shoot apex, Growth, Flowering, Pod set, Multi-locule pods     

An Analysis of the Influence of Plant Density on the Growth of Vicia faba: II. THE SIGNIFICANCE OF COMPETITION FOR LIGHT IN RELATION TO PLANT DEVELOPMENT AT DIFFERENT DENSITIES

In a further analysis of the changing pattern of developmentinduced in Vicia faba by varying the density, it has been foundthat a reduction from a high to a low density has little influenceon the subsequent development unless such thinning is delayeduntil the flowering phase. By this time, save for widely spacedplants, the level of self shading within the population hasbecome marked. In fact, at high densities (55–65 plants/metre²)during the early-ripening phase the light intensity at groundlevel may fall to 0.03 daylight while a considerable proportionof the plant—up to 38 per cent.—may receive lessthan o-1 daylight. At low densities (11-I2 plants/metre²) theminimum intensity at ground level is 0.14 daylight and lessthan 3 per cent, of the shoot is subjected to o-1 daylight.In pot experiments, using a range of screens, it was establishedthat the compensation point is about o-I daylight. Thus, asthe density is increased the light gradient between the apexand the base becomes progressively steeper and the proportionof the leaves not actively assimilating correspondingly greater. To assess the ways in which such a light gradient operates,experiments were carried out in which either the apex or theinflorescences or leaves were removed over different sectionsof the stem or various parts of the shoot shaded and detailedrecords made of development, particularly of flower- and pod-production.Removal of the upper leaves or shading the apex primarily increasesthe rate of pod abscission after the flowers have set. Partialremoval of the inflorescences, especially at the lower nodes,has an opposite effect, while decapitation, though it augmentsthe percentage of flowers which produce immature pods, subsequentlycauses fewer pods to reach maturity. Shading of the lower nodesreduces at these nodes the number of mature pods but may resultin more pods maturing at the upper nodes. It is concluded that when the light gradient is such as to restrictthe internal supplies of substrates the growth of those organswith the least competitive ability, e.g. the newly formed pods,is arrested. It is at this phase that the factors controllingabscission come into play and that abscission is dependent upona balance between the levels of auxins and the production ofan abscission factor.     

Studies of heterosis,combining ability and inheritance of yield and yield components in a diallel cross of bengal gram (Cicer arietinum L.)

Summary A 5 X 5 diallel cross among well-adapted varieties of gram from different agroclimatic regions was studied for heterosis, combining ability and inheritance of days-to-flowering, primary branches, pods per plant, 100-seed weight and grain yield. A high degree of heterosis over mid-parent and better parent was observed for primary branches, no. of pods and grain yield, whereas very little heterosis was exhibited for days-to-flower and 100-seed weight. Crosses among lines of diverse origin generally gave higher heterosis and over-dominance than lines from the same region. Primary branch number, pod number, and grain yield exhibited positive over-dominance; days-to-flower showed negative over-dominance while 100-seed weight had no dominance. Both general and specific combining ability effects were significant for all the characters studied but g.c.a. effects appeared to be more important for days-to-flower, 100-seed weight and grain yield. Graphical analysis indicated additive effects for all the characters, with complete dominance for days-to-flower, no dominance for 100-seed weight and over-dominance for the other three characters. Dominant genes conditioned earliness, primary branch number and 100-seed weight. The role of various parents and crosses in planning a hybridization programme has been discussed.     

Seed Production in Leafless and Conventional Phenotypes of Pisum sativum L. in Relation to Water Availability Within a Controlled Environment

Water requirements in relation to seed production was studiedin near-isogenic lines of leafless (afafstst) and conventional(++++) pea plants (Pisum sativum). The plants were grown toseed maturity in pots in a controlled environment under conditionsof high, medium and low irrigation levels. When each genotypewas irrigated independently and on demand and the soil moisturecontent maintained at 65–80 per cent of full capacitythere was no significant phenotypic difference in water useefficiency (WUE), defined as g d. wt seed per kg H₂O utilized.There existed genotypically-controlled upper and lower limitsto yield between which the total dry weight of seed per plantcan be determined by water availability. There was no significantdifferential effect of genotype or of irrigation treatment onthe number of pods, number of seed, unit seed dry weight andbiological yield per plant. There was significant interactionon stem length, and leaf area at specified nodes. When the wateractually required in relation to the water available was takeninto account, the leafless phenotype consistently utilized 33–38per cent less water and produced a correspondingly lower totaldry weight of seed than the conventional counterpart. Independentlyof regime the total dry weight seed per phenotype remained anear constant proportion of the above-ground biomass. Pisum sativum L., garden pea, leafless peas, seed production, water availability